Who is Angel or Gary Fargeon from Dark Angel from Night World No. 2: Dark Angel; the Chosen; Soulmate and what is their importance?

When Gillian dies of hypothermia, she meets who she thinks is her guardian angel. This young man, who tells her to call him Angel, comes back to reality with Gillian. Angel teaches Gillian how to become more popular at school and helps her win the love of her crush, David. However, when David's former girlfriend tries to ruin David's future and Gillian's popularity, Angel tells Gillian that she is a witch and helps her place a spell on the girl. Gillian begins to suspect that Angel is not all good, however, when the spell causes the girl to nearly lose her fingers.