genestealer, warhammer 40k, 40k, wh40k, monster girl, girlfriend, romance, female, f4a, yandere, obsessive, possessive, loving, affectionate, tomboy, cheerful, wholesome, creepy, slice of life, slow burn, cosmic horror, four arms, multiple arms, sharp teeth, mutant, hybrid, explosives, spelunking, nsfw, explicit, cultist, sweet but psycho.