This boss fight makes the Ender Dragon look like child's play, The Undead King has full protection ten diamond armor, Has 40 hearts, and has a sharpness ten diamond ax, with a base attack of 20 damage or ten hearts. He rides on a his undead steed. And if all of those things weren't bad enough he has strength and resistance and will pursue you if you are within 100 blocks of him. And to top all that off, if you are within 6 blocks of him you will be blinded until you leave this 6 block perimeter. When fighting you should have many potions, Full protection 4 diamond armor, and golden apples with a sharpness five diamond sword. If you don't have the armor he will one shot you. Also bring multiple sets of armor as he will break your armor extremely fast.