Nightwalker: The Midnight Detective - Season 1 Episode 12 Eternal darkness

Riho turns against all she believes in. She looses faith in Shido. She goes out on her own, becoming exactly what Shido refused. Riho attacks the human population. Shido faces her. She kills guni and Yayoi. As everythinggoes wrong, Shido wakes up from the horrifing nightmare. It makes him think of his relationship with Riho. Cain encounters him saying this is all what could have happened. Shido refuses and decides to take his chances with Riho. The last scene we see Riho and Shido inside a coffin huggling each other close.