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.
If you happen to find a Reaper Queen in the rad zone, I recommend not going much further or you will find yourself overwhelmed very quickly! It seems once you run over their spawns they spawn more often, so when you’ve fought a few queens and think to yourself “my health is low, I need to leave” there is very likely more queens waiting for you on the way out!
PLANT SPECIES Z IS YOUR FRIEND: heals your mount super fast and provides a charge light just by standing next to it!
There's a glitch about half way through the baby stage where the baby attacks you regardless of the gland buff this drains it's stamina which will drain it's food to recharge as long as your baby has food in it's inventory it wont starve because of this even if it's food hits zero just feed it like normal and keep a close eye on it