4. Ender Dragon will Respawn. Once the outer pillars and their end crystals are rebuilt, the Ender Dragon will respawn again. You should see the boss bar appear again at the top of the game window.

Does the Ender dragon Respawn after I kill it?

When the player spawns in the end dimension for the first time, an Ender Dragon automatically spawns at 0,0 in the end dimension. But once a player kills the dragon, there is a way to respawn it. If the player places end crystals on each of the 4 sides of the end portal, another Ender Dragon will spawn.

Can you Respawn the Ender dragon with the egg?

No, just place 4 end crystals on the bedrock well straight parts and ender dragon will be spawned.