Defender of the Faith

You summon forth 1 spectral celestial or fiendish (Based off alignment) defender on both sides of you. Together you take formation shoulder to shoulder, holding your shields so that they overlap. Each soldier benefits from the protection of his neighbors' shields as well as his own. Each Celestial or fiend has the summoners same AC and hit points equal to the level of the summoner. Each creature occupies 5 feet of space. While in this shield wall you cannot attack or spell-cast, and attacks made against you or your other defenders have disadvantage. Attacking or losing concentration ends this spell. 

At Higher Levels: For each level above 3rd used you summon an extra defender on each side to a maximum of 5th level.