Sheath apparently was invented in 2014 for New Warriors. She was a member of the society of Orollan (the people who were nearly all killed when Thane's powers manifested).
Anyway, this story definitely seems weird. It's very much a story that doesn't look like it'll have consequences outside of maybe the book it's set in. Since I'm not a regular reader, that doesn't look like it'll appeal to me (although Machine Man is in this book? That's pretty cool!).
Fun dumb fights can be fine, which might be basically what it's going for. It's weird seeing Karnak in his old outfit. It just adds to the whole "not real" feel to the book.