[In part, Yuan does it because-- well, he's never had someone to tell him to stop for his own sake, only because they didn't like what he was doing. It is something he wished he might have had.]

[The rest of it is duty, is responsibility. Kratos is in Yuan's power, and in a very real way depends on him, and it's Yuan's duty to repay that trust. However it developed, which Yuan is still not altogether clear on.]

Apparently Nidavellir is full of new experiences.

[...that might have been in poor taste. Yuan grimaces slightly.]

Don't push yourself, and you'll heal faster. Do you need help reclining?