The Arelius family are mainly shown as a servant family in the Blackflame Empire who are tasked with the maintenance of the Empire's infrastructure, including sanitation or dusting things.
However, there is also an Arelius main branch (House Arelius) on another continent which is a Monarch faction. This began with the First Patriarch, who ascended past cradle and went on to become Ozriel, the Reaper.
The bloodline of the Arelius family possesses the Arelius bloodline senses.
The Arelius Monarch, Tiberian Arelius, is known as the Fallen Monarch and is assumed to be dead or gone. The Arelius main clan is referred to as 'ruined', but they are competing in the Uncrowned King Tournament.
A Sage of a Thousand Eyes and a Sage of Brooms are also mentioned in passing, but it is unknown if these two are the same person or if they are still alive.