Due to 1.9 making improvements towards the Ender Dragon, I decided to make a custom version of my own boss fight. You need to actually summon the New Omega Ender Dragon by dropping the item "Ender Star" into the new well in The End. Then the Ender Dragon will be spawned and will try to kill you by spawning in minions and strike lightning bolts at you. In The End there is a giant tower that prevents you from using your arrows. You need to go into the tower and destroy the purple glass energy crystal in order to use your arrows and destroy the Ender Crystals. Be careful. After eliminating all of the Crystals, something evil will happen.