The folks from Requiem: Bloodymare have released some information about the possession beasts that make an appearance in their MMORPG.
Giont and Rebria like to play. They don't come out that often, so when they do, it's always a fun time.
Possession Beasts are powerful beings that can take the most horrific of monsters and make it beg for its life... Until it has a mouth, that is.
Starting on level 23, players can take the Forgotten Relics quest and obtain their first Possession Beast at the end of the quest-chain. Another way to obtain a Possession Beast is by hunting monsters of level 40 and above.
Once a player's Hardcore Gauge is full, he or she can call upon their Possession Beast (just like they would activate a skill) and use it inflict maximum damage on their enemies.