Multiple Ender Dragons

So... I play on Minecraft Pe and I went to the  Ender for the first time.... I destroyed nearly all the crystals when I got killed. When I came back the whole enderfamily was there waiting for me.... Look at this... I can’t past the end now...

i copied the world and put on creative nothing works unless /kill @e but I want the achievement so I won’t get rid of them with a command