Nyanlathotep is the third & final of the three girls that D gets to receive a smooch from, being the girl in Chapter 3. She is the aunt of Ln'eta, Estir and Rhok'zan. Nyanlathotep also appears in Chapter 2 and the in end of Chapter 4 in Sucker for Love: Date to Die for, keeping tallies of how many times Stardust has died.
She has recently become your roommate as you are on positive terms and also living on your own in this current day sucks.