Rule-of-Three, one of the many sons of Graz'zt.

Rule-of-Three is one of the many Planescape characters out there. I gather he hasn't made many appearances, but he was in Expedition to the Demonweb Pits (which I happen to have a copy of). He is the son of Graz'zt, and his ultimate goal is the unite the three major fiendish races of the lower planes and crush the upper planes.

He poses as a githzerai sage, using his abilities to disguise his appearance in public. He dispenses cryptic advice from the Styx Oarsman, which is a tavern & rooming house in the Lower Ward of the city of Sigil. Most people in Sigil are not aware that he is actually a cambion and the son of the demon lord Graz'zt.

Rule-of-Three

Medium fiend, chaotic evil

Armor Class 22 (studded leather)

Hit Points 105 (14d8+42)

Speed 30 ft.

Str        Dex      Con      Int        Wis      Cha

18 (+4) 18 (+4) 16 (+3) 17 (+3) 14 (+2) 20 (+5)

Saving Throws Str +7, Con +6, Int +6, Cha +8

Skills Arcana +6, Deception +8, History +6, Perception +5, Persuasion +8, Stealth +7

Damage Resistances cold, fire, lightning, poison; bludgeoning, piercing, and slashing from nonmagical weapons

Senses darkvision 60 ft., passive Perception 15

Languages Abyssal, Common, Infernal

Challenge 7 (2,900 XP)

Abyssal Expertise. Rule-of-Three’s proficiency modifier is doubled for Intelligence (Arcana) or (History) checks related to the Abyss. For these checks, he has Arcana +9 & History +9.

Fiendish Blessing. Rule-of-Three’s AC includes his Charisma bonus.

Innate Spellcasting. Rule-of-Three’s spellcasting ability is Charisma (spell save DC 16). Rule-of-Three can innately cast the following spells, requiring no material components:

3/day: alter self, command, detect magic

1/day: plane shift (self only)

Sneak Attack. Once per turn, Rule-of-Three can deal an extra 10 (3d6) to one creature he hits if he had advantage on the attack roll. He must use a finesse or ranged weapon.

He doesn’t need advantage on the attack roll if another enemy of the target is within 5 feet of it, that enemy isn’t incapacitated, and Rule-of-Three doesn’t have disadvantage on the attack roll.

Rule-of-Three also doesn’t need advantage on the attack roll if no creature other than his target is within 5 feet of him.

Actions

Multiattack. Rule-of-Three makes two melee attacks or uses his Eldritch Ray twice.

Dagger. Melee or Ranged Weapon Attack: +8 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 7 (1d4+5) piercing damage.

Eldritch Ray. Ranged Spell Attack: +7 to hit, range 120 ft., one target. Hit: 10 (3d6) force damage.

Fiendish Charm. One humanoid Rule-of-Three can see within 30 feet of him must succeed on a DC 16 Wisdom saving throw or be magically charmed for 1 day. The charmed target obeys Rule-of-Three’s spoken commands. If the target suffers any harm from Rule-of-Three or another creature or receives a suicidal command from Rule-of-Three, the target can repeat the saving throw, ending the effect on itself on a success. If a target’s saving throw is successful, or if the effect ends for it, the creature is immune to Rule-of-Three’s Fiendish Charm for the next 24 hours.

Equipment

Dagger of Venom. You gain a +1 bonus to attack and damage rolls made with this magic weapon.

You can use an action to cause thick, black poison to coat the blade. The poison remains for 1 minute or until an attack using this weapon hits a creature. That creature must succeed on a DC 15 Constitution saving throw or take 2d10 poison damage and become poisoned for 1 minute. The dagger can't be used this way again until the next dawn.

Glamoured Studded Leather. While wearing this armor, you gain a +1 bonus to AC. You can also use a bonus action to speak the armor's command word and cause the armor to assume the appearance of a normal set of clothing or some other kind of armor. You decide what it looks like, including color, style, and accessories, but the armor retains its normal bulk and weight. The illusory appearance lasts until you use this property again or remove the armor.

Eyes of Seeing. These crystal lenses fit over the eyes. They have 3 charges. As an action, you can speak the lenses' command word and expend 1 charge. For the next 10 minutes, you have truesight out to 120 feet when you peer through the lenses.

The lenses regain 1d3 expended charges daily at dawn.

Ring of Mind Shielding. While wearing this ring, you are immune to magic that allows other creatures to read your thoughts, determine whether you are lying, know your alignment, or know your creature type. Creatures can telepathically communicate with you only if you allow it.

You can use an action to cause the ring to become invisible until you use another action to make it visible, until you remove the ring, or until you die.

If you die while wearing the ring, your soul enters it, unless it already houses a soul. You can remain in the ring or depart for the afterlife. As long as your soul is in the ring, you can telepathically communicate with any creature wearing it. A wearer can't prevent this telepathic communication.