A small detail in the Arcane season 2 finale confirms our suspicions about who the next major villain will be in future League of Legends shows
As noted by Dexerto, one small moment in the season 2 finale really ties the whole crow motif together. When a crow at the end opens its eyes and reveals a demonic row of three of them along its head, it's clear that Swain, the Grand General of Noxus, has been keeping an eye on things.