Abyssion

Abyssion is a hidden boss in Tales of Symphonia. On first appearance he looks like a young, sickly man with black hair and a dark outfit. Upon absorbing dark energies from the Necromicon however, his look alters drastically, and he now has bright red spiky hair and tattoos underneath his eyes.

Quest Role
Abyssion is the end boss of the Devil Arms sub-quest. He appears after the player has gathered all nine Devil Arms, and upon his defeat, will unlock the weapons. Despite having the same statistics of their locked states, the Devil Arms will now increase in the amount of physical damage they do proportional to the amount of monsters the specific user has killed.

To start the quest, you must first find Soul Eater or Evil Eye (or both) and talk to Abyssion, who appears in Flanoir. There, he reveals that the Devil Arms are cursed, and gives you the Nebilim Blade and Nebilim Key, which is required to unlock chests that contain the remaining devil arms. On finding eight of the nine weapons, he tells you that he will meet the party in the Temple of Shadow, where he will seal them away for good. After collecting the ninth Devil Arm, the party meet Abyssion and hand him the Devil Arms. He then pulls out the Necromicon, a cursed tome containing forbidden knowledge, and absorbs the Devil Arms energies. The battle then commences.

Many players find that Abyssion is the strongest enemy in the game, as he can use many physical attacks from each character's fighting style. He can also use powerful elemental spell with very little casting time and is very hard to stumble. He also has 180,000 HP, which is almost double that of Mithos' final form.

Trivia
1. The Devil Arms represent each of the characters, but as Kratos Aurion leaves the party Zelos Wilder is able to use two Devil Arms, though his is more powerful, as he will have killed more monsters than Kratos.

2. So long as the party is not over-levelled, the battle with Abyssion can take up to and more than half an hour.

3. In the PS2 version of Tales of Symphonia Abyssion is immune to All-Divides.