[He notes their gasp in delight, then chuckles at their first question.]

Some of us do. That's a little human quirk, though.

[This is...a sweet person, he thinks. He recalls a name...]

Ariel-san. Do you mind if I call you that? It sounds more friendly than 'Mystery'.

[A name of an angel of non-specific gender, an angel Maria has mentioned before. Yes, that's what they appear to be. An angel. The being - who he has dubbed Ariel - asserts they're not human. They're someone who watches, because 'that person' says so. He figures pressing on who 'that person' might be is a moot point. He'll find out eventually.]

...It seems as though you've changed things. Because I'm right here, speaking to you. [He shrugs lightly.] I've met a few - I suppose you could call them 'other beings' before. They called themselves 'not human'. But they had a name. They could speak to me. They were, to their surprise...becoming human.

Because their love allowed them to do so.
You might be changing, too. If you wish it. I can imagine it might be lonely out here all the time.