200 years ago he gave up being a True Dragonlord and turn into a undead using a ritual. Sacrificing millions, collect their souls and became a undead dragon.
And as a undead dragon he can use tier magic but he can no longer produce wild magic. This means the current reserve of wild magic he has stored up from all those millions of souls from that ritual, is the very last reserve he had. His move Soul Breaker that he invented only work if he is a undead and would destroy him too if he was a living being. He only has 3 shots for the rest of his life.
He can't make more wild magic nor repeat the ritual, because he is already a undead.
This also explain why even after 200 years except those initial destroyed countries, there is literally no more movement from him. The world thinks he is dead.
He is now hiding and trying to develop his tier magic using the Corpus of Abyss.
Sure being undead sound cool as he is no longer afraid ( even though he is still a coward). The whole reason why he did it was to conquer his fear. He will feel no pain, control over a million zombies and has a ultimate attack that is the most scary vile magic ever that can be used 3 times.
Bu was it worth it? To give up being a natural True Dragonlord to become a Undead Dragon with a reserve of wild magic he cannot replenish?
Maybe is because i am seeing him as a fool due to the fact Nazarick forces can beat the hell out of him through sheer numbers and not through his view.
As he is unbelievable powerful now against any other lv100 player. But i still feel he kinda gave up the chance to grow as a dragonlord toward a more narrow path that practically had to make him start over by learning tier magic.
But man, he is still a pretty vile thing. He even turn his own species into zombies for his own power. I think if PDL knew where he was and how he turn out, they would actually fight each other. No matter what, Cure Elim has already pass the point of no return. He already crossed that line that must not be crossed.