Timaios appears in Corridor stages n with n=x*8+6. Rarely drops a Tendai Uyaku. After defeating it, there is a chance to obtain its skin which can be used when merging minions. This minion's skin has the skinventory-ID 5.
All bosses in the Eternal Corridor use infinite Mana, which allows them to use their attacks as often as they wish. Constantly uses its Fang - Absorb Mana + Power and Claw - Absorb HP + Power attacks.
Hints on defeating this boss
Use minions resistant to Absorption like Hirasag, Skwimel, and relatives.