yasuo is one of their side laners along with jax because smolder doesnt do well on his own so yasuo is the easiest gank on the enemy team compared to jax. yasuo has built in shields plus they tend to buy immortal shieldbow (this one did too) so serpents fang really makes sure you can walk up to him and bully him for free gold without him even being able to fight back really. serpents fang most likely isnt just in their build every game.
