Cassiok Shadowdusk

Medium Aberration, Chaotic Evil

Armor Class 14, 17 with mage armor

Hit Points 99 (18d8 + 18)

Speed 30 ft.

STR

DEX

CON

INT

WIS

CHA

Saving Throws STR +2, DEX +4, CON +3, INT +11, WIS +8, CHA +5

Skills Arcana +13, History +13

Damage Resistances damage from spells; nonmagical bludgeoning, piercing, slashing, (from stoneskin)

Senses passive Perception 12

Languages Common, Deep Speech, Infernal, Undercommon

Challenge 12 (8,400 XP)

Traits

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

Special Equipment. Cassiok carries a staff of power that grants him a +2 bonus to Armor Class, spell attack rolls, and saving throws. His insectoid physiology prevents him from making melee attacks with the staff. If reduced to 20 hit points or fewer, Cassiok uses his next action to break his staff in a retributive strike.

Spellcasting

Spellcasting. Cassiok is an 18th-level spellcaster. His spellcasting ability is Intelligence (spell save DC 19, +11 to hit with spell attacks). Cassiok 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): phantasmal killer, 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

*Cassiok casts these spells on himself before combat.

Lore

Cassiok Shadowdusk is a middle-aged man transformed by prolonged exposure to the Far Realm. Although his head remains human, his body is that of a giant beetle that walks on its hind legs.