Yeva is a side quest boss in dragonspyre, gone bad supposedly by her time in the crystal web. After you defeat her, she threatens to return and come after you.
But she never does.
I was thinking that it might be a storyline that could continue sometime after the end of Polaris. Maybe Old Cobb might have found her, and now that he isn't quite as happy with you as he was, made it possible for her to take revenge. He's a spider after all, and she's a spiderkeeper - looks after and takes care of spiders. She'd be someone close to his heart.
However
Since she was a side quest boss, she would only come back and come after you IF you did the side quest in dragonspyre.