honestly there aren't many xtx cannibalism fics which is a bummer bcs xtx lore has so many things that can be interpreted as cannibalism... but here are some fics that i really like https://archiveofourown.org/works/51748474 (sgyu, not really cannibalism but i really do love this a lot)
https://archiveofourown.org/works/57057556/chapters/145110613 (beomjvn, cannibalism and necrophilia)
https://archiveofourown.org/works/50924347 (taegyvkai, forced cannibalism)