the "Maru-yu" we know ingame and in works is actually a collective body of the Type 3 Submergence Transport Vehicle.
So basically there are many Maru-yu, each one is the same, while being different.
Onee-chan!Reason for doing her bestMaru-yu-san, do you have a moment?*toc toc*and old memoriesA very farGeez!
I told you I'm not a mole!Yeah.Do your best, Mole-chan.Maru-yu will do her best at the expedition!