Minecraft wiki entry for Gathering_resources_on_peaceful_difficulty, associated text: When you enter the End, the ender dragon will spawn. It cannot do damage to you but it will still knock you back, so the only things that are dangerous are that the dragon may push you into the void, or inflict falling damage when you are destroying end crystals. Apart from that, the fight should be easy. You can also use the end gateway portal and you will be able to access the End as much as you want. However, end crystals cannot be obtained in Peaceful, because ghast tears are unobtainable, so you cannot respawn the dragon.