Eidolon - Fighter

Pride always comes before the fall, but what if pride ensured that you would never fall. An Eidolon is a Fighter whose sole purpose is to die. It is an entity that is held together by its own pride and ego after suffering potentially thousands of defeats and would-be fatal injuries. Instead of using their magics to summon armies or enchant others into doing their bidding, Eidolons use their magics to give them intensive energies and focus in combat. Eidolons would not sit at the top a tower conjuring magics to defend it, they would be at the entrance ready for any challenger that dare enter its domain

The Eidolon's phylactery is arguably the most complicated. The final step in a fighter's ritual to become an Eidolon is to find an equally or stronger opponent and fall in combat by any means. Not only must the would-be Eidolon intentionally die, but the opponent they lose to must be filled with pride and/or boast about their victory. If successful, the fighter's soul invades the body of the victor. The now phylactery retains its own soul but also gains all of the experiences that the first had gained as well as all of their pain and the ritual is complete

The Eidolon's do not have a phylactery per say, it simply exists to fight and continue to spread pain throughout the lands. Eventually after enough times of dying and invading another's body, the amount of pain that the victor intakes brings them to madness instantly. The Eidolon can still die of old age which is why it must continue to fight and eventually die by someone who can best them in combat and feel pride for it

The only way to truly end the curse of an Eidolon is to kill it and feel no sense of pride. Even the victor being internally proud of their accomplishment is enough to continue the spread of the curse