Links for Mango on other Sites (non-isekai)

Hades and Persephone Ficlets

Webtoon - Greek Mythology Shorts

Nevermore

Webtoon - Shoujo Ai in Afterlife Academy

Leonore wakes up without memories and meets other girl. They walk to academy, where they find out that they are dead. Getting first places in academy means new shot at life. Girl Leonore worries about turns out to be unwilling to continue friendship and avoids her.
Flashback shows Leonore as Noble Lady, whose brother died in accident as he saved her during storm

Monsters and Girls

Webtoon - Saphic succubus and angel

My New Life as a Slasher - Webtoon

Comedy. Guy dies and ends up in body of slasher. Employs help of side and Main characters to get back home

Winged

Bird FL and ML. She lives in cage but he saves her eventually. She is cute and helpless while he becomes obsessed with protecting her. Yandere antagonist

Atnomen

Yandere monster guy

Marionetta

ANTIstalker

Vampire School. ML has ability to control lower ranking vampires. Yandere

The Deals We Make

The Blind Prince