Matsu
Mahavir was gathering a few used-up books of stamps (why did no one ever tell him when they’d emptied one?) when he heard the approach. Ah. Ah, this sounded like one of those. He had little time to brace himself but attempted to anyway as Matsu shouted.
Matsu “What the [freak] is this?!”
Thankfully they continued before he could automatically offer the very helpful answer of “a letter.” He had to be a little more careful than that if he didn’t want punches or chairs or anything to start flying. …Not that he could always prevent that, either. At least the older woman might help…? Though she didn’t seem especially pleased, either.

“…” He hesitated long enough to feel sure they were finished… for this round.
Matsu “Did you write these? Who told you anything about me?! What gives you a right to pretend to be him?”

“Um, I don’t even know your name, Mx… And I’m afraid I hardly have time to sort all of these. Writing them all myself would be…” Would it be too much right now to say impossible? Probably. He just gestured slightly. “They appear of their own accord, as you’ve likely seen. I, ah, have no intention of pretending to be anyone but myself.”
Time to see how that went.