[Diluc's hands visibly tighten on the empty tea cup he's still holding. He wants to scream, to throw the cup against the wall, to somehow resume his march northward to wreak havoc on Snezhnaya for the sins they've committed and continue to perpetrate. Given the impossibility of that last task given that he's trapped here in this dream world, he'll even settle for finding Tartaglia and beating him within an inch of his life. Or worse.

He does none of these. Instead, he sits in stony silence and simply fumes. His occasional dreamotion firebird, usually no larger than sparrow, erupts out of him in a spew of fiery rage and flies outside through the nearby window, where it erupts into something large, burning, and terrible in the sky before dissipating.

At that point, the pressure of his hold causes the teacup to shatter and the pain of the broken porcelain against his skin snaps him back to reality. With a grumbled swear, he tosses the remains onto the table in front of them. His hand is bleeding. He doesn't notice.]

Because of the effect that Delusions have on the people wielding them.

[There's a knowing grimness in his tone.]

I left my Vision in Mondstadt when I left and used my father's Delusion for three years. It probably took years off my life.

[That admission, more than anything that Diluc's ever told Thoma, is a sign of trust. It's a secret that no one else knows except for Kaeya, and an action that even now he can't explain or defend.

But telling Thoma, of all people, seems... correct. Somehow.]