How do you get the Nightbringer Yasuo Icon?
It was a mission or event reward. Riot's description in the client reads: “Earned by participating in the 2017 VS. event.”
Is the Nightbringer Yasuo Icon still available?
No. Riot tied the Nightbringer Yasuo Icon to 2017 (mission reward), and it does not normally bring back past event rewards or bundles.
