Characters ended up saving the Baron from The Shade and formed an alliance of convenience. For his bodyguards I just used Gladiators from MM pg. 346.
Armour Class 15 (studded leather)
Hit Points 142 (15d8+72)
Speed 30 ft.
STR 11 (+0) DEX 16 (+3) CON 14 (+2)
INT 13 (+1) WIS 11 (+0) CHA 11 (+0)
Saving Throws Dex +7, lnt +5
Skills Acrobatics +7, Deception +4, Perception +4, Stealth + 11
Damage Resistances poison
Senses passive Perception 14
Languages Thieves’ cant, Gothic, Common, Hallit, Orc
Challenge 12 (8,400 XP)
Evasion. If The Baron is subjected to an effect that allows him to make a Dexterity saving throw to take only half damage, The Baron instead takes no damage if he succeeds on the saving throw, and only half damage if it fails.
Lucky (3/Long Rest). The Baron is lucky. He may reroll any d20 roll after he see the result, however, he must accept the next roll. He may only reroll the same die once.
Sneak Attack (1/Turn). The Baron deals an extra 13 (4d6) damage when he hits a target with a weapon attack and has advantage on the attack roll, or when the target is within 5 feet of an ally of The Baron that isn’t incapacitated and The Baron doesn’t have disadvantage on the attack roll.
Sap Adept. The Baron is a master of the use (and misuse) of the sap increasing its damage and DC (included).
Multiattack. The Baron makes two sap attacks and one arc pistol attack
Sap. Melee Weapon Attack: +8 to hit, reach 5 ft., one target.
Hit: 29 (7d6 +3) bludgeoning damage, and the target must make a DC 17 Constitution saving throw or become stunned for 1 round.
Arc Pistol. Ranged Weapon Attack: +8 to hit, range 50 ft., one target.
Hit: 7 (1d8 + 3) lightning damage.
Combat Gear EMP grenades (3), flash grenades (3), concussion grenades (6), potions of lesser restoration (3), potions of cure serious wounds (2); Other Gear +2 chain shirt, +1 buckler, arc pistol, sap, amulet of natural armor +1, cloak of resistance +3, handy haversack, ring of protection +2, discipline facet (see page 63)