[Belthazar says nothing else until they are settled and strapped in. He keeps his head down and his eyes closed, obviously trying to conserve his strength.]

... I should tell you that draining mana hurts. It hurts a great deal, as mana is tied to one's life force. If you could channel your mana into something else, like a crystal, then it would be fine. But if I'm directly feeding from you, I... I know it will not be pleasant for you.

[His knuckles turn white against his black robes.]

If you do not want to do this, it's fine.