When one becomes evil their soul turns into a Kishen soul and they most be taking down and their soul devoured. When this doesn't happen and the evil soul continues to grow it becomes a full fledged Kishen a monster of pure evil. Asura is a special case as only weapons have been known to turn into Kishens but when he devoured the soul of his partner Asura became a Kishen. Being near a Kishen can make a person go insane and his soul wave length alone can turn an entire town crazy. Asura is a skilled myster and has super human strength and speed beyond that of Death himself. Asura also has a second form that turns him into a giant and a 3rd form where he is at his most dangerous. His greatest weakness is his own sanity which causes him to have panic attacks. A formidable foe indeed and one of the more powerful in the tournament.
Born a human Ken Kaneki lived a fairly normal life. One day a terrible accident happened nearly killing Kaneki; the only way to revive him was to give him parts of a ghoul. A Ghoul is a being who feeds off the flesh of a human; Kaneki had to give in to his new life style or starve to death, naturally he chose the life of a ghoul. Kaneki has super fast speed and super strength. He uses the tentacles on his back to scale walls and attack his opponents. Kaneki's greatest weakness is his human side as he every now and then has to make a moral choice based on his old life as a human. Kaneki is a force to be reckoned with for sure can he take down the evil Kishen Asura?