Armor (Light)

Very Rare Requires attunement by a spellcaster aligned with the Abyss Requires Attunement

Whenever the wearer uses casts a spell to summon a creature from the Abyss, the spell counts as being two levels higher for the purposes of calculating AC, damage and health. Additionally, the wearer may cast "Summon Fiend" in its "Demon" form once without spending a spell slot. They regain the ability to do this upon finishing a long rest.
Finally, should you have a demon under your influence, it has Disadvantage on any saving throws to escape your influence.

In ancient times, the Twilight Elves crafted weapons of pure darkness to wield against the surface dwellers. Some of these weapons were living, drow slaves taken from the pits to serve as the arms in a war of genocide. Tortured, broken and possessed, these Tobthach were sent to surface as one-man apocalypses. The cities they were sent to were given one choice: surrender or die.

This armour, with its chitinous warm embrace, was worn by the Tobtach sent to claim Stenhode for the Twilight King. It is made from the scales of a massive Rot Dragon, with abyssal sigils carved into it that seem to weep darkness. It gives its wearer a deeper connection with the Abyss, and the ancient words of mastery carved into it gives the wielder power over the creatures of the darkness.