Belphegor (Lord of Sloth)

Devil's Sight. Magical darkness doesn't impede the archdevil's darkvision.

Abyssal Weapons. The archdevil's weapon attacks are magical and deal an extra 5d8 necrotic damage on a hit (included in the attacks).

Magic Resistance. The archdevil has advantage on saving throws against spells and other magical effects.

Innate Spellcasting. The archdevil's spellcasting ability is Charisma (spell save DC 24). The devil can innately cast the following spells, requiring only verbal components:

Cantrips: Mending, Swordburst, Thaumaturgy
At will: Detect Evil and Good, thunderous speech, Suggestion, Spike Growth,
3/day each: aura of fear, Wall of Steel, Contingency, Summon Fiend,
1/day each: Unholy word, Power Word Stun, symbol of pain, Mighty Fortress, Guards and Wards

Multiattack. The devil makes two attacks with its weapon.

Magic rod: It acted as both a rod of rulership and a powerful staff of striking.
Melee Weapon Attack: +14 to hit, reach 5 ft., one target. Hit: 12 (2d8+3) bludgeoning damage plus 22 (5d8) necrotic damage.
Rulership. You can use an Action to present the rod and Command obedience from each creature of your choice that you can see within 120 feet of you. Each target must succeed on a DC 15 Wisdom saving throw or be Charmed by you for 8 hours. While Charmed in this way, the creature regards you as its trusted leader. If harmed by you or your Companions, or commanded to do something contrary to its Nature, a target ceases to be Charmed in this way. The rod can't be used again until the next dawn.
Impact.The Rod has 10 charges, you can spend how many charges you want at once to enhance an attack. For each charge spent, add a 1d8 to the attack. If 5 or more charges are used at once roll a d20 and if a 5 or lower is rolled, the rod loses its magic.
Jet of Acid. A jet of acid hoses out from the rod forming a line 150-foot long and 5 feet wide. Each creature in the line must make a Dexterity saving throw. A creature takes 8d6 acid damage on a failed save and 2d6 acid damage at the end of its next turn, or half as much damage and no damage at the end of its next turn on a successful one.

Teleport. The devil magically teleports, along with any equipment it is wearing or carrying, up to 120 feet to an unoccupied space it can see.

Shapeshifting. The devil magically polymorphs into a humanoid that has a challenge rating equal to or less than its own, or back into its true form. It reverts to its true form if it dies. Any equipment it is wearing or carrying is absorbed or borne by the new form.

Devil Trigger. Starting at 3rd level, you can use your action to unleash the divine energy within yourself, causing your eyes to turn into pools of darkness. The instant you transform, other creatures within 10 feet of you that can see you must each succeed on a Charisma saving throw (DC 8 + your proficiency bonus + your Charisma modifier) or become frightened of you until the end of your next turn.

Your transformation lasts until you end it as a bonus action. During it, once on each of your turns, you can deal extra necrotic damage to one target when you deal damage to it with an attack or a spell. The extra necrotic damage equals your level.

Once you use this trait, you can't use it again until you finish a long rest.

The archdevil can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature's turn. The archdevil regains spent legendary actions at the start of its turn.

Detect. The archdevil makes a Wisdom (Perception) check.

Teleport. The archdevil magically teleports, along with any equipment it is wearing or carrying, up to 120 feet to an unoccupied space it can see.

Beelphegor’s Touch (Costs 2 Actions). Could have two effects, each devastating on their own but when used in concert could easily fell the most dangerous of foes. The first effect allowed him to turn flesh into iron, rendering almost any organic foe an inert statue. The second effect almost instantly corroded metal, rusting up to a 10 ft (3 m) cube worth of material into useless pieces in an instant.