In this case they are religious figures who are charged with watching over and purifying the region's legendary, Lustrorius, since they are the only beings capable of resonating with it (or should be anyways, Vos bypasses that with copious amounts of gaslighting and drugs after he steals the legendary off of the last lorekeeper prior to Suzuen)
Like the avatar, each one inherits the memories of their predecessors though Suzuen's got fractured due to his own predecessor being gunned in the head (the memories eventually came back towards the end at least)