[Guido]

Animation and hand drawing was way downhill and scrapped in the fifth episode, nonetheless, it gives enough information for the audience to understand what's going on.

Yukino's private conversation with Ranmaru.

Spoiler:

Her father is conducting a project involving Neo-Darwinism and evolution. Organisms that have shown resilience through thousands of years to change their cellular make-up to adapt.

It implies a strong connection with the phantom larvae functioning as symbiotic bacteria to improve other organisms.

Yukino also discloses to Ranmaru that they Oni hand she showed him in the picture was found five years ago at the site of the Machida complex; the Oni hand that resembles that of the demon that almost slaughtered Ranmaru in the previous episode.

Professor Shiraishi.

Spoiler:

Indeed, his research deals with experimenting on the Phantom and carcass collected at Machida five years ago.

Experimented on himself and his crew to let the phantoms mutated them in order to prove his theory of evolution.

He reveals that the the recent phantom outbreak and the massive genocide happening at Machida in the past begins with an occult circle of alchemists way back centuries ago in Europe.
They made a puzzle box that functions as link to other netherworlds. Once all the puzzles' piece are set in their proper places, the puzzle opens a door that leads to a nether realm of demons. It seems that the alchemists paid with their lives for transgressing a boundary it was never meant for man to cross.

The box shattered in 108 pieces, and since then the door has remained open for the demons to cross as gateway to our world.

Ranmaru's tattoo.

Spoiler:

Tokko and Professor Shiraishi realize that Ranmaru has 'one' of them within him. A phantom residing in his spirit and has proved to save the boy's life for the last two episodes, as also granting him regeneration capacities.

But, everytime that Ranmaru makes subconscious use of its powers the Phantom is gradually taking over, as the tattoo on his right arm continues to expand. That's why Sakura warned Ranmaru to stay away from the phantoms so as not to put himself in a dire circumstance to be forced to drawn upon th help of his inner Phantom.

This was a fulfilling episode for twenty minutes in terms of plot, but for the last two minutes I felt the staff was rushing too much the pace.

Spoiler:

The mutated prof being chopped in a matter of seconds by the mysterious boy and girl who got there before TOKKO did, and the latter pretty much know who the two mysterious figures are just looking at Suzuka's assured eyes.

Next week TOKKO airs 0:40 a.m., and it looks to be an episode focused on Suzuka as the main character.