Claudius knows how Lan Wangji loves, how fiercely and how endlessly -- I have never known how to feel anything by halves, he'd said, or how to love with any reservation. Lan Wangji was once a young man who touched no one, and now whenever he returns a touch, he grasps back with both hands. I have also never known how to take back my love once it is given away. He said that, too. It struck Claudius to his soul, the realization that after countless cycles of fairweather friends and temporary allies, he found a friend whose love would never leave him.

Lan Wangji loved Wei Wuxian, and trusted him. He loved and trusted his brother, but his brother was wrong. Loving both, he had to act, and the next move was uncertain. That uncertainty must have been agony.

"Ah," he says, and lets it say all of that. He touches Lan Wangji's hand.