Arakune

Information
A black blob-like creature with a white mask who formerly worked alongside Tager and Litchi in Sector Seven. After an attempt to study the Boundary, due to his inferiority complex over Kokonoe's genius, he became what he is today, now housing innumerable insects with his now-blobby body and thriving on knowledge. His horrible condition has rendered him virtually insane and lacking any reliable memory, as well as distorting his speech to near incoherency - most of his dialogue consists of gibberish, insane laughter and tortured screaming.

His dialogue between many characters, as well as his Arcade Mode ending, suggest that it was the power and knowledge he obtained from the Boundary that gradually turned him into what he is, and notably (according to his Arcade Mode ending) he doesn't seem to have noticed that he's changed, and to him, his bizarre speech is completely normal. He seems to not understand why others can't understand him, creating a crude mask for himself thinking it would allow others to understand what he's saying.

He currently lives in the sewers of Kagutsuchi where the Seithr concentration is highest and will attack anyone who visits there. He has also been known to attack and devour his victims to sustain himself, specifically targeting the Kaka Clan, the closest living creatures. He thirsts for power and knowledge above all else and considers the Azure Grimoire the pinnacle of such. Anytime he meets Ragna he becomes obsessive in his desire to consume the Azure.

In Continuum Shift, Arakune continues to look for the Azure Grimoire. He is also shown to be capable of speaking normally like a normal human, although temporarily before slipping away to insanity once more. During his sane mode, he told Litchi to cease her attempts to cure him using the same power that drove him mad and instead turn herself to Kokonoe for healing; there is a fine line that she shouldn't cross or she could end up like him. An encounter with Terumi later reveals that Arakune was used as an experiment to create the Black Beast, but he ends up as a failure as the only thing he knew is only how to consume others.

Powers and abilities
Stepping into the Boundary has transformed Arakune into a black, amorphous creature. Added with his erratic nature makes him a difficult opponent to overcome. He is able to dive into the ground as a puddle and sink into the ground to avoid attacks and render himself invisible to enemy detection until he is struck. His gooey body encompasses a swarm of poisonous bees to keep the pressure on. His body also contains a bundle of bones which he can shapeshift for a variety of melee attacks or shape it into a cannon that can fire a concentrated beam of dark energy.

Trivia

 * Arakune's Guilty Gear counterparts seem to be in the form of Eddie/Zato-1 and Zappa. Largely borrowing from the former, aside from his shapeshifting nature, Arakune sacrificed his own sanity and eventually memories for knowledge and ended up being consumed, much like Zato sacrificing his own eyesight for control of the Forbidden Beast born of his own shadow, which eventually kills him. From the latter, he has similar gameplay traits in the form of summoning various creatures that inhabit his own body.
 * With Rachel and Hakumen, Arakune is one of the few without a skeleton shown upon the first's lightning attacks. Though, unlike the two, he just appears black and white. This is thought to further count for the fact he can't return to a human state; plus ruin the "straight-forward fighting".
 * Arakune's real form is a topic of most. Some see him as a regular scientist (Lab coat, glasses, ect.) while others see him handsome with black hair. The true form of Arakune is yet to be shown, however will most likely be revealed in the future.