The ancient entity from the divine RPG mod. Basically, imagine a hostile iron golem that is around 5-10x the size of the player with 800 health, long attack range, and throws you into the air. It's almost impossible to gear near him with melee, since you're forced to use range. And you would run out of arrows before killing the boss.
To actually survive the hits, you wear elite realmite armor or anything that prevents fall damage.
And if you want to beat him? You have to craft a ranged weapon with long range and infinite ammo.
Atleast you can obtain phasers and blitz weapons after you beat him atleast. Which are both ranged.