Fire Assimilation is one of Agni's unique transcendental skills. It is regarded as the symbol of the Fire God Agni. It assimilates with fire, and neither gravity nor the law of conservation of mass have any effect on the user. The speed of movement is so fast that it looks like teleportation. Whenever Agni moves to a destination with no fire, he uses Fire Assimilation. (When the destination has fire, Immortal Fire is more efficient in regard to travel distance and vigor consumption than Fire Assimilation.)
Until Fire Assimilation is lifted, he is close to invincible, but the only problem is that vigor continues to be consumed.