Unfinished. Not final product.
He has a low chance of parrying your attacks. They're deadly depending on the tier of your armor or absorption. He also heals on kill and overcharges at random when taking damage, giving him the opportunity to heal while being unable to take damage.
He has lines for when he is summoned or for when he kills a player. Most notably he will set you in survival if you summon him in creative using the tablet.
Additionally he may also speak to player(s) at random times in the world.
being set to survival mode after summoning
After you've been killed by him, he might refer to you as 'boss'.