Cassiok Shadowdusk

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

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.

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

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

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

Level 3 (3 slots): counterspell, fly, lightning bolt

Level 4 (3 slots): phantasmal killer, fire shield, stoneskin*

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

Level 6 (1 slots): globe of invulnerability

Level 7 (1 slots): teleport

Level 8 (1 slots): mind blank*

Level 9 (1 slots): time stop

*Cassiok casts these spells on himself before combat.