Sources
CR
Type
Size
Alignment
Movement

Zorhanna's Simulacrum

Medium Construct, Neutral Evil

Armor Class 12, 15 with mage armor
Hit Points 99 (18d8 + 18)
Speed 30 ft.
STR
10
+0
DEX
14
+2
CON
12
+1
INT
20
+5
WIS
15
+2
CHA
16
+3
Saving Throws INT +9, WIS +6
Skills Arcana +13, History +13
Damage Resistances damage from spells; nonmagical bludgeoning, piercing, slashing, (from stoneskin)
Senses passive Perception 12
Languages Common, Deep Speech (when it is angry or frustrated), Draconic, Elvish, Gnomish, Sylvan
Challenge 12 (8,400 XP)

Traits

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

Simulacrum. The simulacrum can't regain expended spell slots or use the properties of the shard solitaire necklace. (The shard solitaire is currently attuned to the Far Realm entity trapped inside.) If the simulacrum drops to 0 hit points, it turns to snow and melts away, and the shard solitaire necklace teleports to the safe in Zorhanna's vault tower.

Spellcasting

Spellcasting. The simulacrum is an 18th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 17, +9 to hit with spell attacks). The simulacrum can cast disguise self and invisibility at will and has the following wizard spells prepared:

Cantrips (at will): fire bolt, light, mage hand, prestidigitation, shocking grasp

1st level (4 slots): detect magic, identify, mage armor*, magic missile

2nd level (3 slots): detect thoughts, mirror image, misty step

3rd level (3 slots): counterspell, fly, lightning bolt

4th level (3 slots): banishment, fire shield, stoneskin*

5th level (3 slots): cone of cold, scrying, wall of force

6th level (1 slot): globe of invulnerability

7th level (1 slot): teleport

8th level (1 slot): mind blank*

9th level (1 slot): time stop

*The simulacrum casts these spells on itself before combat.

Actions

Dagger. Melee or Ranged Weapon Attack: +6 to hit, reach 5 ft. or range 20/60 ft., one target. Hit:4 (1d4 + 2) piercing damage.

Lore

Archmages are powerful (and usually quite old) spellcasters dedicated to the study of the arcane arts. Benevolent ones counsel kings and queens, while evil ones rule as tyrants and pursue lichdom. Those who are neither good nor evil sequester themselves in remote towers to practice their magic without interruption. An archmage typically has one or more apprentice mages, and an archmage's abode has numerous magical wards and guardians to discourage interlopers.