He’s trying to smile a bit, just for you and your silly jokes, but he he can't, it's not natural for him.—You don't remember the last time you saw him smile or laugh, and he doesn't remember it either.

One day, you went out with Blade for a walk in Xianzhou Luofu.—While you were walking together, Blade noticed that you stopped and turned around to see you.

As soon as he saw you with your phone in hand and saying 'Smile!', he did it naturally, he smiled.