Theory on future Darkin.
This has probably been stated before but with Rhaast's and his weapon's release one of their interactions with aatrox mentions how death and war being together will be "delicious" . Since we already know Aatrox is war due to him causing conflict that would make Rhaast death due to him just wanting to kill everything himself instead of having others do it in his stead. This would lead me to believe that the theme for the Darkin are that they represent the four horsemen of the apocalypse. Which leads me to believe that if Varus is a darkin or darkin related he would be best suited to be strife due to him seeking revenge on Noxians. Now the biggest problem with this theory is that there are five Darkin not four so the fifth one could break the theory. Post thoughts or suggestions below.