Here are the characters that played a part in Nelle's story:

Nelle Benson (of course)

She is the witch and the one who has Michael's baby.

Michael Corinthos

He is one of Sonny and Carly's sons. The other son, Morgan, died.

Sonny Corinthos

Five words. Do not mess with him.

Carly Corinthos

She is the wife of Sonny and the mother of Josslyn. Nelle used her grief over the loss of Morgan to make think her that she was crazy. Nelle also lied that Carly pushed her down some stairs.

Josslyn Jacks

She is the daughter of Carly, and her father is Jasper Jacks. She takes a liking to Nelle, but soon realizes that Nelle is just a scum.

Chase

He is a police officer and helps Michael take down Nelle.

Ava Jerome

She becomes friends with Nelle and is also a witch.