This is episode 29 of 40 of Bloody Mary: Her Summoned Love. Play it below, then continue straight into the next episode — the whole season is free and needs no account.
The closing stretch of the season, where the arc pays off.
A bullied girl accidentally summons the Grim Reaper in the mirror—only to discover he's her past-life lover who died for love. She fights her way up from the bottom of campus to avenge her family, gradually turning the blood-soaked spirit back into the beautiful young man whose eyes hold only her.