If you plan on battling reaper king, have a decent mount that can tank and possess an AoE attack/push back attack. Killed one on a Spino in 3 minute. Smaller animal will get killed easily. Difficulty 6 server setting for reference and vanilla stat modifier.
Since i cant find this anywhere. Reapers take reduced damage naturally so its a good soaker. Dont bring light pets near theese because they take more damage and deal less damage.The reaper burns when light is near it. Nameless will attack it tho. Sorry for bad english.