I don't know if this is the same as Dungeon deai, since I haven't read that one (it is in my read list).
Weed's dark enough to me, his greed is insatiable, to the point of squeezing or wringing every last bit of thing he can use, literally. Normally people don't go that far (let just say he is like Uncle Scrooge). But then again, his actions, although not for charitable act, is motivated by the need to care for his family, especially his little sister. Even if he didn't realized it, he actually did care for others, that's why I said he is kind, (his teammates, his teacher, etc).
Okay that's enough rant about Weed ^^
While answering all of your question, I'll talk more about the series.
The story starts with 4 people from different world summoned there to become heroes, they are:
Amagi Ren - Hero of Sword, 16 years old, High-school student. Bishounen (more to the girly type) and cool.
Kitamura Motoyasu - Hero of Spear, 21 years old, University student. Handsome guy, and easy going.
Kawasumi Itsuki - Hero of Bow, 17 years old, High-school student. Calm and well mannered.
Iwatani Naofumi - Hero of Shield, 20 years old, University student. typical unsociable otaku, but friendlier and easygoing.
They are summoned from japan, albeit different world with the world Ren, Motoyasu and Itsuki came from are far more advanced in technology than where Naofumi came from. After that, the King, Orto Clay Merulomarg, explained that the 4 heroes are summoned to repel the calamity that threaten the kingdom of Merulomarg. They cannot return to their world unless they finish the task of saving the world. The king also explain about Status Magic, a magic in this world which enabled people to check their own status. Naofumi checked his status and he found:
Name: Iwatani Naofumi
Job Class: Shield Hero Lv1
Equipment:
- Small Shield (Legendary Equipment)
- Clothes from another world
Skill: None
Magic: None.
The King then told them to rest, and they go to the guest room, checking and learning about their weapon. Naofumi found that they weapon are equipped with Help function (Tutorial, glossary, etc) and Translation function (Automatic translation of this world language by speaking and listening, not writing). After that they each talked a bit about themselves. They each agreed that this world are really game-alike. Ren and Motoyasu added that this world system are somehow similar to the game in their world (Their world already embraced the VRMMO technology). Itsuki only play consumer game but at least has basic understanding, only Naofumi who has very little knowledge, therefore, making him an amateur. The other three ridicule him a bit, saying that Shield class is unpopular, loser class that only has good defense at start but later on will hard to catch up with others.
The next day, They gathered in front of the King. They are required to travel separately from other heroes, therefore several people from the castle will join them in their adventure as party members. Result:
Ren: 5 people
Motoyasu: 4 people (3 girls)
Itsuki: 3 people
Naofumi: 0 people.
The King explained that there are rumor about Naofumi being an amateur than the rest (apparently someone is eavesdropping on the heroes chat yesterday) making him even more unpopular. In the end, one girl, Mein Sufi from Motoyasu party joined him. The King gave Naofumi 800 gold to recruit new talent, while the others only received 600 gold. Naofumi then goes to purchase new equipments but he then learned he couldn't equip weapon, making him even more hopeless for an offensive. Naofumi, by suggestion from Main buy a chain mail, and new equipment for Mein. They head out to the plain area outskirt of the city. Naofumi has difficulty fighting since he has very low attack (punching), but on the other side, he doesn't even feel pain from the monster attack. Mein comfort him. Later, after fighting a bit, they rested at inn, on different room. The next day, Naofumi found all his equipment (clothes included) and his money (except small changes) disappear. All that left is his shield in his wrist (and boxer pants). Naofumi goes to the room next door, but didn't found Mein. Still not understanding what happening, he deduced he is robbed by thief. Suddenly, two soldiers roughly bring him back to the castle, there he found Mein, is sobbing, while the King, other heroes and people there looking at him with contempt and hatred. When Naofumi going to report he is being robbed, the King bellowed at him, Naofumi couldn't understand. Mein then explain that Naofumi forced himself on her. Naofumi tried to plead for his innocence, however no one believes him. He is even more shocked when he sees his chain mail, is equipped by Motoyasu. Mein makes a mocking gesture, sticking her tongue out at him (unseen by others), and Naofumi finally realize he is betrayed, not only by Mein but also by the King and other Heroes. It is all clear that at the start of his summoning, no one is looking at him as hero, but a nuisance, everyone is making fun of him. He is soon filled with anger and throw the rest of money he have to Motoyasu. The King couldn't execute Naofumi as he is still a Hero, so he pardoned him, but will not support him anymore. Naofumi walks away, and on that day, the rumour spread far, his reputation goes down hill and he lost everything...
2 week later, he managed to get several money from selling drop items to pay for new cheap equipment at the weapon shop. When people still ridicule him or making fun of him, he let them taste Balloon monster hidden beneath his cape to attack those people (if you look at the cover of vol 1, you will sea orange monsters under his cape, Naofumi intentionally keep those monster for this kind of occasion. He is fine since his defense his very high, thus he didn't feel any pain at all even when bitten). Not only his personality changed drastically, he is even more known notoriously for his unfriendly attitude and bad deeds. Later he learned more about his shield, His shield can absorb any material and parts of monster, fulfilling requirement needed for unlocking new shield, and granting him increment in stats and new skill. He can change the form of his shield, to use many skills granted by the shield (later he will acquire skills to increase quality of item he made, ranging from food, medicine, weapon, armor, etc). There is only one problem, he cannot adventure alone. No matter what, he is not suited for attacking, he can only defend himself and others, therefore he need party members. But he didn't trusted other, they will someday betray him. At this time, someone offer him a solution: purchasing slave. Slave will never betray their master, because they are controlled by a magic to force their master order unto them, any act of betrayal or desertion will kill the slave. At first, he is offered a werewolf at Lv66, but Naofumi refused, as it is not useful on long run. Naofumi asked for small and cheap slave, saying even if it's weak, he will train them. Then Naofumi managed to get a slave at cheap price, sickly little girl at age of 10 who is a Human Beast of Raccoon race (Merulomarg is a country with human right, so there will never be human slaves, however Sub-human or Human Beast are exception). This slave name is, Laftalia / Raftalia.
Naofumi ways of adventuring is party style and he is on supportive role. The shield grant him boost in stats, mainly defense and new skill to use such as imprisoning target, heal, guarding, etc.