So the abyssal is the tail...and the human body is...well, "former" human....I see.
I've seen something similar in Bleach: 3rd Phantom game on Nintendo DS.
One of the major characters transformed into an Arrancar-Shinigami hybrid, and he lost any human emotions---and to top it off, he also has a similar form to Re-Class's tail when he goes into his final form.
The concept of abyssals are actually very similar to Hollows....including the fact that the more humanoid they are, the stronger they become.

where is some micro filament wire and a Nazi Werewolf when you need them for this bitch here!?

Twin drives?!!

Fking chaos and their mutant spawn.