hi! yeah, try these:
http://www.mangago.me/home/mangalist/846256/?filter=&page=1
http://www.mangago.me/read-manga/maou_ni_natta_node_dungeon_tsukutte_jingai_musume_to_honobono_suru/
http://www.mangago.me/read-manga/the_hero_who_seeks_revenge_shall_exterminate_with_darkness/
http://www.mangago.me/read-manga/remonster/
^this one's probably closest to the slime one, it also has the world building aspect
Uhm, does anyone have any Isekai recs where the mc is reincarnated as a monster/ sword or something nonhuman ? it can be a demon king or someone whos a bad person idk. like not a saintess or anything?something like That Time I got Reincarnated As a Slime?