Artist's commentary
Champion's Trophy
Valentine's return gift from Santa Karna.
A shiny golden champion's trophy made in the shape of a fist. Obviously it's not made by some boxing association, but by Karna himself, using some of his golden armament. Which means...
He did it! Again!
It may not have any particular functions, but it is likely valuable on a Noble Phantasm level, given the material it's made from.
...Are you sure it's okay to give this away? (Second attempted question)
"Of course. This is a champion's trophy. Its true worth is in the act of presenting it to someone as proof of their victory. I apologize the materials are secondhand, but I hope you don't mind too much."
Uh, that's not the issue here.