Aegishorn Valorplate

This suit of armor is called Valorplate. It is reinforced with an adamantine-corundumine steel alloy, and infused with powerful magic that is unbreakable by normal means. While you're wearing it, any critical hit against you becomes a normal hit, you are immune to Acid damage, and non-magical attacks cannot pierce the armor. 

You can also summon an Aetherial Otyugh as a bonus action once per long rest that can attack your enemies. It moves on your initiative and lasts until it's hit points drop to 0. It cannot be dispelled or banished. You may use an additional bonus action to unsummon the creature.

 

Plate consists of shaped, interlocking metal plates to cover the entire body. A suit of plate includes gauntlets, heavy leather boots, a visored helmet, and thick layers of padding underneath the armor. Buckles and straps distribute the weight over the body.

Notes: Immunity: Critical Hits, Immunity: Acid, Immunity: Bludgeoning, Piercing, and Slashing from Nonmagical Weapons, By a being of unnerving intimidation, Combat, Warding, Str. 15 Required, Stealth Disadvantage