Who is Thena to Thanos?

So, I'm curious here - can you elaborate on the relationship between Thena and Thanos? I mean, from what I've gathered, they both seem to be characters from the Marvel Universe, but I'm not entirely clear on the specifics of their connection. Is Thena a member of Thanos's army? A close ally? Or is there some other dynamic at play here? I'd love to hear your thoughts on this!