Ch1
Carrying on from end of Vol20, Saito is in the elven submarine thinking about how he could be two Void familiars at once. He's also worried about Louise and co who might be coming after him after he was captured. Saito also now calls BS on Vittorio's claim that the way to solve the Windstone Catastrophe is somewhere in the Holy Lands, the Rhyme Dragon named 'Ocean Mother' have been living there for 6,000 years and a artefact as powerful as that can't have gone that long without being sensed by her. Saito also tried to ask Derf about the new runes, but Derf isn't responding.
Trained warriors such as Ali aren't also trained in healing magic. So Tiffania need to get somewhere better to be healed, and soon. But the elven sub is slower than warships and the elven navy is running a blockade. They plan on reaching a border city between the desert and Gallia (albeit one not acknowledged by the Senate) and then go into Gallia from there. Fatima wakes up at the end of this chapter.
Ch2
-Louise and co reaches elven capital, and Colbert decides to ram their airship into the Senate's meeting tower, because the elves won't expect this. Since he thinkd they're already crazy enough to attack the elven capital, they're crazy enough to do this. Guiche helped reinforce the prow before collision and Siesta barely manages to wake Louise up before then (for those who care, this is by whispering how flat Louise's chest is repeatedly). Malicorne helped firing the Tiger Tank's main gun that Colbert installed onto the airship. Their plan is to kidnap some high ranking elf so they can swap for Saito.
Ch3
Colbert leads the group into the building. They were intercepted by three guards on the way. Colbert's Fireball that's 4x more powerful than a normal Square mage's spell got blown apart by one of the guard's wind spell. Guiche's Valkyries got curbstomped in melee when Guiche tried to help.
Colbert pulled a 'You Shall Not Pass' using his Flame Snake against the three guards so his students can move on and grab someone. Colbert dual-casts with two Flame Snakes and then shoots 3 Fireballs to cave in the ceiling. Colbert then used alchemy to fused the fallen rocks to hold down the guards, but they morph it back almost immediately to escape the trap.
Tabitha stayed on the airship to protect it, and faced off against 3 other guards. The guards didn't have Counter, so Tabitha shot into melee distance and took them down with a vacuum blade and icicle spears, against elves' preconception of human mages being casters needing time and standing at the back, and that allowed her to gain the upper hand at the start. Tabitha's foot was caught in softened ground and a elf nearly cut her down, but Tabitha parried it with her staff and dropped a Square class Blizzard (normally a Triangle spell) on herself to save herself. After that however a hooded elf came by and nearly took down Tabitha with Counter, and after he took the hood off he was revealed to be Bidashal.
Colbert ended up catching up with Louise and co as he ran away, chased by his 3 guards. Giant stone arms was conjured from the walls to stop them all. Guiche asked if they can just say sorry and leave, which Louise shot the idea down, since even if they can speak the elven language after the ramming it won't work. They found a windstone-powered elevator and Colbert barely managed to get it to work before their defences to buy time were overwhelmed. Before going too far though the elves crumpled the elevator and everyone got out before they were crushed.
Louise blew apart the stone arms with a Explosion, emptying her low willpower reserves (after a giant Explosion that got them to bypass the blockade back in Vol20) allowing them to reach the Senate meeting chamber. They're faced with dozens of elder elves, and the older elves get the more magically powerful they become, so they're vastly outmatched. The elven senate leader gave Louise and others the chance to surrender, they refused, and he conjured a stone giant to apprehend them. The stone giant had Counter as well, the Spirit helping being the Senate Tower's, so they needed Louise to take it down. Louise charged right in, since the elves can't risk killing her, and launched a Explosion at point blank range. It wasn't powerful enough and Louise was caught, and other Triangle class spells to try and free Louise were all Countered.
Right before Total Party Kill, Louise felt Willpower being channeled to her from Saito and she cast a Explosion powerful enough to win. Louise threatened to Explode all the elders, while Tabitha somehow managed to escape from Bidashal to ambush the senate leader and they demanded Saito to be returned to them. The senate revealed they don't have Saito, who have escaped the capital earlier.
Ch4
After Fatima woke up she resisted, and from the way she talked about Tiffa Saito was tempted to hurt her. Then he realized much of it was bluster and she was afraid because of 'demons' of the Void are in front of her. Saito refuted Fatima's claims that Tiffa and her mother had it good living in luxury while the rest of their clan was exiled because of their race traitor crimes, telling how Tiffa's mother died, and Fatima only laughed and said it served them right. Fatima is revealed to be Tiffa's cousin. Tiffa tried to kneel and apologize for what her and her mother had done to their clan, and Fatima was enchanted to sleep by Ali during the struggles. During all that Saito felt the Lifdrasil runes turning his life energy into Willpower for his linked summoner, even if he got the Gandalfr runes from Louise and not Lifdrasil. Saito felt his body going cold, falling into a abyss, hurt all over, dizzy, and ultimately like his very existence was being torn to shreds.
Derflinger finally responded to Saito and explained the Lifdrasil runes. The Lifdrasil uses up its life for its summoner, basically as a magic battery. Saito decided if he's being drained it means Louise is in enough danger to use his life up, and he decided dying for Louise isn't that bad. Derf says Lifdrasil's life expectancy is at least a few spells so Saito shouldn't die just yet, and Tiffa held Saito close until the effect stopped. Tiffa also cried that it was because of her turning Saito into her familiar that Saito will die.
The elven sub then reached the navy blockade and almost sunk to bombs being dropped on them. Fatima being captured didn't stop bombs coming. Rukshana decided for them to abandon ship and swim to land using magic.
Back to Louise and others, they captured the leader as a hostage and are returning to the airship. The speaker revealed the Iron Blood Alliance within the Senate had shelled Dragon's Nest, Saito's last known location, and it's unlikely Saito survived. Louise refuted that claim, knowing Saito was alive due to the Lifdrasil power-up earlier. After getting back to the ship the leader broke free, having faked being overpowered, and Bidashal appeared to tell them to take the two of them back to humans' leaders. The leader want to broker a deal himself since the Senate refuses to come to a decision, and while the elves will win in the end they would take massive loses, which both Bidashal and the leader wants to avoid. Louise was convinced that this is the best way to go, as stopping the war is more likely to lead to Saito's survival than trying to look for him in the ocean like looking for a specific grain of sand in the desert.
Ch5
Saito and others abandoned ship. They planned on leaving Fatima behind to her own devices, but Tiffa begged them to take her with them. Ali felt the leader of the Iron Blood Alliance won't rest until they found their corpses, so they're likely to still be chased.
Derf is sorry that he can't be any more help to Saito, and Saito hypothesized that it's because Derf was Sasha's sword that there's a mental block that prevents Derf to speak of everything all this time. Derf commented that Saito should be more worried that Louise will find out that he kissed Tiffa, and Saito begged Derf to stop act like he's not a part of all this.
Back in Halkegenia, the nations assembled their forces, though due to recent warring only Romalia has a whole force while others are worn down. Henrietta asks Vittorio for progress on rescuing Saito, while suspecting Romalia would kill him and find the next hosts if that would be easier. Henrietta also asks if war is the best way, and felt if she regret her path then she can't face those who have died already in wars like her one against Reconquista. Vittorio on the other hand felt he can't afford to feel regret.
After Henrietta left, Julio reported in on Louise's progress and Vittorio said the Round Mirror confirmed Lifdrasil have been summoned. Julio was saddened and sincerely wished he could have been friends with Saito, but Saito won't live much longer when the Four Fours assembled. Vittorio says at least Saito and one of his beloved 'Saints' will be remembered as Heroes by Halkeginia in death.
Ch6
Saito and others reached a city, a trading outpost between Sahara, Halkeginia and Rub al Khali. Originally this city was for exiled elves, far from the Sahara and abandoned by the Great Purpose. Ali and Rukshana left the others at a hospital while they left for Halkeginia to try and stop the war. A bit of 'romance comedy' here where the female elf doctor thought Tiffa's affliction was her overly large breasts before the gunshots were revealed.
Saito was left guarding Fatima when he was told he can't help healing, having neither magic or training. Fatima was only faking unconsciousness and tried to kill him. They eventually called a ceasefire since Fatima was too hungry to continue. Saito tried to do street performances for money to buy food, using one of their fights as a 'mock' performance. Derf said this reminded him of the old days where Brimir and Sasha also used Gandalfr powers for performances like that, so Saito shouldn't feel bad for using legendary powers this way. Fatima revealed she used to live at the outpost with the rest of her exiled clan, before she was picked up by the Iron Blood Alliance. Saito eventually released Fatima, saying he can't be bothered keeping guard on her but actually feeling sorry for her past, and that the Iron Blood Alliance apparently didn't care enough about her being hostage they were willing to bomb her with others. Fatima was told however the next time she tries to harm Tiffa Saito will not be so lenient.
Later Saito ran into the weapons shop owner that sold him Derf. The shop owner was here looking for more weapons to sell to the Crusade. Saito asked the shop owner to pass on the message that he's at the outpost.
The Iron Blood alliance leader in charge of the navy didn't find the bodies, and concluded the only place Saito and others could run to was the outpost. He decided to bomb the place with Firestones, after hearing reports that this was possible in Gallia. Fatima and other elves being there was treated as no concern, to him and the rest of his men they're all blood traitors.
Foquet was infiltrating the navy and found that out. She left immediately to protect Tiffania as to her Tiffa's like a daughter.
Ch7
Henrietta is still suspicious of Vittorio, and was willing to make a deal with the elves like she originally planned with Joseph to stop the war. Louise and others finally reached where she and the army was. Louise was brought to meet Halkeginia's leaders for debrief. Henrietta positioned Vittorio to admit out loud he's willing to sue for peace if it was possible. Louise then asked Colbert to bring in Bidashal and the senate leader. Emperor of Germania Albrecht III said they should take the elves hostage, which they refuted 1) they're elected officials, they are replaceable, and 2) even with the Void the Iron Blood Alliance is planning on mass Firestone bombing to escalate - and everyone present knew of when Joseph used only a few to destroy armies, and the elves planned on using them en masse. Henrietta blamed the elves for being barbaric for that action, while they retorted if it weren't for humans the elves won't even know exploding Firestones as weapons was possible for all these thousands of years. Vittorio is willing to accept peace, but said the return of the Holy Land was a non-negotiable condition. The elves are willing to consider this, as long as the rest of the Sahara is untouched, which raised Henrietta and Louise's suspicion more - if they're willing to let the Holy Land go this easily then does the artefact that could save Halkeginia really exist?
More 'romance comedy' stuff, like Guiche and others meeting back with the rest of the Undine Knights and considering if Saito would really fall for Tiffa, since he's weak to big chests. Also more shipping between Malicorne (M) and Eleanor (S). Louise overhears that and asks Siesta how likely is Saito stepping out, and Siesta admits freely it's likely. Louise says she'll forgive Saito, until Siesta raised the possibilities of kissing with tongue and the *cough* various things Tiffa can do with her chest and Saito's 'sword' *cough. Louise went mad at that and Siesta's cracks at her flat chest.
Vittorio brought Bidashal and the senate leader to the Round Mirror, and showed them the past. The Variag were biologically close to humans but had better metallurgy. Elves and humans were at peace and had cities where they could co-exist. Gandalfr Sasha is confirmed to be 'Saint Anubis'. And from the elves' POV, the 'Founder' is the god equivalent for humans. Brimir 'went empty' and nuked the elves' main city using Sasha's Lifdrasil power to fuel him. Vittorio accepted the deal that as long as Halkeginia has the Holy Land they would leave the Sahara alone. The Senate Leader and Bidashal thought Vittorio is even more of a fanatic than the Iron Blood Alliance, even more untrustworthy, but they can rely on him speaking the truth on that one thing.
Ch8
Bidashal left to inform the senate of the deal. Vittorio prepares their own trump cards against the Firestone bombing by giving Louise the Incense Burner, Music Box, and what's left of the Ring of Andvari. Vttorio wants Louise to obtain the "Founder's Void", something stronger than Louise's Explosions that could end a fleet. He says each Void Heir have specialized systems within the Void, his was 'Movement' and Tiffania's is 'Forget'. Only Louise, who summoned the Gandalfr, can use the Founder's Void. The Prayer Book revealed to her the "last and strongest" Void, named Life. Louise sank to her knees after reading it, horrified, and even Brimir only cast it once in his lifetime. Louise described this spell as capable of ending the world.
Later, Louise secluded herself to try and come to grips with the responsibility of using that spell, and Yosette (Queen of Gallia) came to meet her. Louise asked if Yosette is afraid of the power and responsibility, of what it can do - Yosette is in a similar position, going from nobody to a Void Mage. Yosette said she won't be afraid or regret what she has to do, because of her love for Julio. For love Yosette'd do many things, and Louise wonders if that just means she doesn't love Saito enough.
Louise returns to her room and talks with Siesta, bringing up another point that if Louise let herself go she might become worse than Joseph. Siesta assured Louise she'll be fine, and then Louise was called up to Henrietta as the sword shop owner came in to report where Saito is. He got 500 gold coins out of this, enough for a commoner to live in luxury for a year. Vittorio then advised Louise to not go to Saito, her Void doesn't belong only to her now, and for Henrietta to not send the Undine Knights to Saito because it'll raise unwanted attention. Vittorio wants to take take of this using Romalian forces only, going as far as threatening Louise with Heresy charges if she does not comply. Henrietta countered with Vittorio interfering with Tristain's internal matters, and Louise isn't his tool, so Louise has her permission to go get Saito.
Louise was planning to cover the 200 miles using Teleport alone, before Kirche reminded her she'd run out of willpower before she gets there. They rode Sylphid away with other Undine Knights and Eleanore sending them off.
Mazarin talked with Henrietta, saying he and Queen Marianne would be proud of Henrietta standing up to Vittorio. Mazarin reminiscences the trio that rode off reminded him of Centurion and his group years ago (KSS protagonists), true heroes from a time where nobles were most like nobles.
Fatima was caught by the Iron Blood Alliance in the outpost, and for not agreeing to Firestone bomb the city and that "there is no elf" in the city for them all being race traitors, she is captured and forced to detonate the Firestones at ground zero.
Ch9
Tiffa woke up from healing, and talked with Saito. She says she's sorry for falling for him and giving him trouble. She then says since her mother was a mistress she can be one for Saito too. In ages past when the elves had royalty the elf king had a harem too. Saito considered it, a option where everyone can be satisfied, but then considered how Louise might feel and decided against it. Before he can convince Tiffa either way Rukshana came in (haven't left yet, was getting supplies) and told Saito she helped him for academic interest's sake, if he brought harm onto the elves she'll be against him. Saito promised he'll do all he can to stop the war, then Ali came in and told them the Iron Blood Alliance surrounded the town.
Foquet arrived then, saying she's there to get Saito and Tiffa out. She confirmed she's hired by Romalia and have orders to kill Saito if she couldn't save them. After analyzing how likely it is for the extremists to bomb the city (very), Saito decides to stay and prevent it somehow - from what he had saw the city doesn't deserve to die. Foquet tried to get Tiffa away anyway, Tiffa's more important to her than the city, but Tiffa managed to get Foquet to stay and help. The bomb is set in the Sofia Temple (I assume Halkeginia's equivalent to Hagia Sophia/Ayasofya Mosque), a place where the elves gather to pray and where massive spirit power resides. Without Void tinkering the Firestones need extensive rituals to prime and explode.
Ch10
Saito and others began to sneak into the temple. Fatima is tied up next to a large pile of Firestones. Saito and others ran into resistance, and Saito stayed behind to buy time. The elite elf he fought shook off a grenade, and had magic body armour strong enough to shrug off auto handgun bullets. Saito stepped onto a exploding trap, but before he was finished Wardes saved him.
Foquet played distraction, and ran into another team Romalia hired - the Elemental Siblings. They revealed they were paid 300,000 gold, to which Foquet complained they're getting paid much more than she did. They were a match for the elf guards, and Damian's ability is revealed to be a alchemy specialist - focusing on speed at the price of precision.
Back to Saito, Wardes helped him fight his way out, and given Saito's emotional turmoil with Wardes that made Gandalfr more powerful. Wardes stayed behind to buy time for Saito to escape, and Saito told him to not die since still needed to make Wardes pay for tricking Louise, while Wardes want Saito to live so he can settle the debt of taking away his left hand. Wardes used Ubiquitous Wind to split himself into eight clones to fight.
Ch11
Ali, Rukshana and Tiffa fought into the Temple as well. Sylphid found the outpost on fire when they got there, but couldn't get close from air in fear of being shot down. They found the Elemental Sibling and almost attacked them, before seeing Foquet as well which pointed them to the Temple.
Ali and others have a boss battle, the Iron Blood Alliace leader managed to take control of Ali's sentient blade set and turned them against Ali. The alliance leader boasts he's on the same level as Bidashal, and was distracted trying to shoot Tiffa while going on about how all barbarians and demons has to die. Fatima took advantage of that and ruined the ritual site, before the leader tried to shoot her. Tiffa ran in to try and save Fatima, so the leader decided to kill Tiffa first.
Saito shot in and knocked the leader away, but couldn't do more due to Counter. Louise made it in time to save Saito before he was crushed. Protecting Louise while casting made Gandalfr operates at 100% power, and Louise cast Dispel on Derf so Saito can beat the leader. Before he went down the leader decides to suicide bomb by using a pocket Firestone - setting up a ritual was only for the fuse, if they just wanted it to explode they can just smash the stone. Dispel only feeds Void energy into it and make it blow up worse, never mind Exploding it away.
Louise still had the Music Box though, and with it it gave Tiffa a new spell. Saito wordlessly told Tiffa to go ahead and use it, even if he has the Lifdrasil runes that might hurt him. Tiffa learned Disintegrate, phrased as making the world forget something existed. Crisis averted at the last minute, but Saito fainted from the spell use.
Final chapter (of the volume)
Saito woke up on the Ostland, having slept for 2 days. Louise was by his side all that time. The Iron Blood Alliance was arrested. Louise kissed Saito, was going to go further, before Malicorne blocked them and told them they left the intercom on and the whole airship could hear them going on and flirting earlier. The rest of the group came in and told each other what went on while Saito was gone.
The war seems to be avoided, with Albrecht III holding the army back while Vittorio and the rest of the Void Mages will meet at the Holy Land. More intimacy scenes between Louise and Saito. Louise confronted Saito about being Lifdrasil. Saito tried to assure Louise that he won't die, and now that there's peace he might not be needed to fuel the Founder's Void - from what he understands it it's basically a magical nuke.
Tiffa visits Foquet and Fatima. Fatima asks who is she supposed to hate now. Tiffa thought if she never met Matilda she might have ended up like Fatima. Tiffa says Fatima doesn't have to hate anyone anymore, and Fatima broke down in tears.
The Void mages & familiars met the senate leader and Bidashal at the Holy Land. They descended into the ocean with magic bubbles. They met Ocean Mother. They went to the weapon cache Saito found when he first got there. Then, Vittorio revealed there is no artefact to save them all, but they needed the Holy Land anyway.
Vittorio cast World Gate, using the full incantation - the longer the Void Spell is chanted, the more powerful it is. Vittorio is offsetting the willpower cost by opening the giant Gate Brimir left behind rather than fueling the spell solely by himself. The Big Reveal - the Markey race that uses magic in Halkeginia came from Saito's Earth to begin with, and the 'Promised Land' the World Gate is connected to is Saito's world.
Vol21 End.