She's incredibly powerful but spellcard battles rely a lot on grace and precision, they're just duels. Mr. Ren doesn't seem like the type to respect then, both he and Kaoru would go in for the kill I'm sure.

I know she can hold her own, but I'm still worried. I...

If she's killed a second time then everything I did would have been in vain, I don't want that to happen! I died because I thought it would protect her but I can't protect her like this!