Digimon Chronicle X

Ten years after activating the X-Program, killing 98% of existing Digimon and creating a new Digital World, King Drasil sends some of the Royal Knights to the old Digital World to check on how it is faring. To aid their journey, they are given the X-Antibody, transforming them into Kentaurosmon X, Craniamon X, and Jesmon X. The Dark Area, created by GranDracmon, was unaffected by the X-Program due to being on a separate layer to the Digital World, with the Seven Great Demon Lords being unaffected due to this. GranDracmon kills Digimon in the old Digital World, forces them to undergo Death-X Evolution, and then sends them to the Dark Area. Taking advantage of this, Laylamon sends thousands of sealed away Digimon to break through the barrier and escape, successfully doing so after she undergoes X-Evolution and defeats Examon. Lucemon's plan is to use this to its advantage, so that it can use the X-Antibody and the other members of the Demon Lords to kill the Royal Knights, then destroy every Digital World in existence.