Phobio is a proud and provocative lycanthrope , not to mention that he is sometimes quite aggressive and cheeky.
Phobio arrives in Tempest with the intent of taking it over, as he thinks Rimuru is weak. Phobio soon is angrily dealt by Milim as he attacks Rigurd as he arrives. Phobio, humiliated by Milim, leaves Tempest after a peaceful talk with Rimuru. Soon after, Tear and Footman sense Phobio's anger, and convince to become a Demon Lord to combat Milim. All he must do is let Charybdis possess his body and maintain control. Phobio breaks the seal on Charybdis, and as Charybdis, he sets attack against Milim. As Charybdis is heading towards Tempest (where Milim is), Rimuru realizes that Charybdis has possessed Phobio. By Rimuru's request, Milim defeats Charybdis while sparing Phobio's life. After the battle, Phobio apologizes for all the trouble he caused, and his master, the Demon Lord Carrion, in another way to apologize, establishes a non-aggression pact with Tempest.
- Leopard Fang Flaming Palm: Essentially a powerful fire punch.
- Ultraspeed Regeneration: Phobio inherited Charybdis's regeneration power after they were fused and separated.
(At least in the beginning): He regards Rimuru as a "lowly slime" who couldn't possibly rule over all of the monsters of Tempest and couldn't possibly rule over (at the time) 30% of the Jura Forest. He thinks Rimuru is a weakling and a phony.
Initially, Phobio had tried to use force to take control of Tempest, as he saw the country of the Jura Forest a worthy area for Karion, only to fail when he later was defeated by Milim, which causes Phobio to hate her as it left him in a situation where he had to return to Karion empty-handed for failing diplomatic relationships. He is scared of her and what she is capable of. Phobio is only a minion of Karion and he knows that Milim is one of the most powerful Demon Lords, surpassing even his master, therefore far surpassing him as only a minion. Even the sight of her makes him uneasy. He does swear to take revenge on her one-day, however.
He respects the Beast King thoroughly. It is unknown what role, if any, he will continue to play in the Beast Kingdom after his shenanigans with Charybdis.