2015- SKT Kalista, Kalista was released 11-20-2014 (No ADs were released in the calendar year 2015, but this was after Season 4 had ended)
2016- SKT Jhin, Jhin was released 2-1-2016
2017- SSG Xayah, Xayah was released 4-19-2017
2018- IG Kai'Sa, Kai'Sa was released 3-7-2018
It's likely due to the small pool of champions, but it's interesting how this role seems to make its new champions meta right away
