Celestial’s Grand Duel

You make a call to beings of the celestial realm for a show. The targeted creature makes a wisdom saving throw, if failed, an arena materializes around you and the targeted creature, only visible to the two of you, with celestial beings in the stands. During the spell’s duration, neither you nor the creature is able to know where other creatures are, you gain advantage on all attacks made against the other creature, and attacks made by you have an additional die added. Hits made against you from the targeted creature do not break concentration, and if you are attacked by a non targeted creature, the attacker takes 4d8 psychic damage. If either you or the creature falls unconscious, the spell ends. When the spell ends, damage taken during the spell, unless unconscious, is halved, rounded down.