For as diverse as the overworld is compared to the other two dimensions, it seems strange that it only have the elder guardian as a boss, I propose we have a second air based boss, called Phobetor. Phobetor would be summoned by sleeping in a bed wearing a phantoms head, (dropped at random from killing a phantom,) and waking up when it's still nighttime. Phobetor takes on the form of a large phantom, about nine blocks wide and four blocks tall. It's wings would have shining stars on them, and his belly would have purple armored plates instead of tan ones. Fighting Phobetor would require fast paced switches between melee and ranged, as he summons two phantoms to swirl around him to take attacks for him if you try and shoot. Phobetor would have two attacks, first it would swoop down and simply try and hit the player, the second is flapping its wings to try and push the player down so the two other phantoms can hit you, (this gives you slow falling so the two phantoms can hit you,) during this time Phobetor is susceptible to ranged shots. Appon death Phobetor would drop a pair of boots called Fear Walkers, which make mobs who get near you scared and run away, Phobetor also drops 5-20 phantom membranes.