It's an important plot point that Asuma finally understands what the "King" of the Hidden Leaf is. At this point, he also stops smoking.
At first I thought it had something to do with his fight over Sora, and being forced to reckon with the relationship he had with his own father.
But, later on, we find out Kurenai is pregnant.
Is this the reason Asuma comes to understand what the king represents, and why he decides to quit smoking? Did he know she was pregnant before or after this moment of understanding?