Leatherhead
Possibly a Idiot.
Armanite (MToF)
Despite recent trends to add depth to monsters, demons are still mostly shallow, being violence incarnate and bent on the consumption and/or destruction of the natural world. Armanites are what happens when someone looks at a centaur and says “What if we make that into a demon?” Though they are used by Demon Lords in place of cavalry, don’t expect to be able to ride them into battle, their insatiable bloodlust makes them fight everyone all the time, even their would-be “allies.” Best you can hope for is to point a herd of them in the direction of the enemy, and watch them blast everything to pieces.
As befitting creatures intended only for combat, the Armanite has a multitude of attacks, and a multiattack that allows them to use 3 of them at once. Used primarily as a shock trooper, you can expect them to employ their 60’ speed to rush into the enemy ranks, let loose a Lightning Lance against the group, and mop up what's left using their melee routine. With their lightning resistance and proclivity for friendly fiendly fire, they don’t care who or what becomes collateral when they let loose with the Lightning Lance, zapping their own team if that lets them kill more. As a tip, even though the Multiattack says to attack with Claw, Hooves, and Tail, it’s best for the Armanite to lead with it’s Hooves attack, potentially forcing the prone status and granting advantage on the subsequent attacks.
The changes to the Armanite are honestly an improvement all things considered. More hp, removed Magical Weapons trait. The claw does a bit of extra lightning damage, and the hooves can knock prone. Just taking something described as being feared for having multiple attacks, and actually making those attacks do even simple things like prone, goes a long way to making a monster more than just a sack of HPs, even if their entire schtick is to be a sack of HPs that smashes other sacks of HP.