Dragon Magazine Annual 5 (2000) had an article about Tharizdun-related monsters, entitled "Children of Tharidun". I concerted one of the creatures (the Rogue Eidolon) to 5e:
Rogue Eidolon
Large construct, chaotic neutral
Armor Class 20 (natural armor)
Hit Points 114 (12d10 + 48)
Speed 30 ft.
STR | DEX | CON | INT | WIS | CHA |
20 (+5) | 10 (+0) | 18 (+4) | 4 (−3) | 6 (−2) | 18 (+4) |
Damage Resistances bludgeoning, piercing, and slashing from nonmagical weapons
Damage Immunities poison, psychic
Condition Immunities charmed, exhaustion, frightened, paralyzed, petrified, poisoned
Senses darkvision 120 ft., passive Perception 8
Languages understands the languages of its creator but can't speak
Challenge 9 (5,000 XP)
Actions
Multiattack. The rogue eidolon uses Blood Spray if it can. It then makes two melee attacks.
Slam. Melee Weapon Attack: +9 to hit, reach 10 ft., on target. Hit: 18 (2d12 + 5) bludgeoning damage, and the target must succeed on a DC 16 Wisdom saving throw or the creature can't take reactions and rolls a d8 to determine what it does during that turn. On a 1 to 4, the creature does nothing. On a 5 or 6, the creature takes no action but uses all its movement to move in a random direction. On a 7 or 8, the creature makes one melee attack against a random creature, or it does nothing if no creature is within reach. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.
Blood Spray (Recharge 5-6): The rogue eidolon spews a gout of thick blood from the seeping symbol carved into its face at a target within 30 feet. A creature struck by the blood spray must make a DC 16 Wisdom save or be afflicted by a terrible madness that causes the target to see all friends as hated enemies. On each of its turns, the target will attack its closest ally immediately. The target can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.