Well one day someone's going to know what they are.

And just as much he wouldn't know what a Levin sword is... but if she could draw it and explain it... he is the man to ask for crazy weapons! Crazy shit is his passion.

"Hey, kinda surprised but if that's what suits you best, it's yours, Robin." He didn't even mention a price or anything akin to it, like a debt or a trade of favors.