I had about 2 or 3 people ask me that question already and no. i have an angela and she's still with me and i caught up on ALL her quests (that i know off) at no point druing any of her quests does she leave your party even when searching for her sister and the next place she has to get to is to visit hell to find a demon... (so you know her death quests is really close) even the quest for her sister was rather hard.

aniways demonblader, (or anyone with this question) if there are any quests that someone told you about ask them where it is and i will go take a look. thank you.