[Ignoring any 'sword polishing' jokes the immature brain wants to toss up. Bakugo won't assume Aki knows of Tsusumaru's true nature until the guy confirms it. Hinting it or even asking about it to find out are also off the table, since he doesn't want to open up the curiosity if Aki doesn't know. So this is left to the devil hunter to suss out and explain himself while they're together. Bakugo will operate on the "doesn't know" side of things.

Looking for swords is nothing more than something a hobbyist or passing interest would suggest. Ancient Japanese palace? Sure, go for the swords. Why not?

His boots grit against the occasional dirt or gravel left on the palace floor, treading on plant vines or dead leaves along the way. Is there a map of this place? Such a thing probably wouldn't be available for download, at least nothing that showed the secrets and vaults. Bakugo searches the net to see if there might be a visitor's hand guide at least. He hears Aki move behind him, obviously intending to follow before his words confirm it.]

If there was an attack, most of the artifacts would be moved to a vault or some place for safe keeping for the duration.

[That much is obvious, but the question of where the vaults are, and if they're open, is the big one. Still, nothing says they can't wander and maybe find less valuable replica?]