Paladin Party Boon

When an adventuring party containing a paladin fights evil creatures, the paladin and his allies are protected against certain types of creatures: aberrations, celestials, elementals, fey, fiends, and undead. Creatures of those types have disadvantage on attack rolls against their targets. The targets also can't be charmed, frightened, or possessed by them. If the targets are already charmed, frightened, or possessed by such a creature, the targets have advantage on any new saving throw against the relevant effect. The duration of this effect on the paladin's allies, per encounter, is {Paladin Level(s) rounds}. The paladin herself enjoys this protection perpetually.