What to do with Dehya

I have been playing this game for a little over 4 months and within that time when it came standard banner 5 Stars characters I have gotten Tighnari as my first and then ever since I have only gotten Dehya I don't know what to do with her. I don't know what teams to build with her. I don't even know what she does but she won't leave me alone so I'm taking that as a sign that I need to build her. What is she good for? I will try to comment what characters I have in the comment section but like I really need help. I normally love team building but I can't think of a single thing to do with her