Sources
CR
Type
Size
Alignment
Movement

Oshundo the Alhoon

Medium Undead (mind flayer, wizard), Neutral Evil

Armor Class 15 (natural armor)
Hit Points 150 (20d8 + 60)
Speed 30 ft., fly 15 ft. (hover)
STR
11
+0
DEX
12
+1
CON
16
+3
INT
19
+4
WIS
17
+3
CHA
17
+3
Saving Throws CON +7, INT +8, WIS +7, CHA +7
Skills Arcana +8, History +8, Insight +7, Perception +7, Stealth +5
Damage Resistances cold, lightning, necrotic
Damage Immunities poison
Condition Immunities Charmed, Exhaustion, Frightened, Paralyzed, Poisoned
Senses truesight 120 ft., passive Perception 17
Languages Common, Deep Speech, telepathy 120 ft., Undercommon
Challenge 10 (5,900 XP)

Traits

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

Spellcasting

Spellcasting. Oshundo casts one of the following spells, requiring no material components and using Intelligence as the spellcasting ability (spell save DC 16):

At will: dancing lights, detect magic, detect thoughts, disguise self, mage hand, prestidigitation

1/day each: dominate monster, globe of invulnerability, invisibility, modify memory, plane shift (self only), wall of force

Actions

Multiattack. Oshundo makes two Chilling Grasp or Arcane Bolt attacks.

Chilling Grasp. Melee Spell Attack: +8 to hit, reach 5 ft., one target. Hit:14 (4d6) cold damage, and Oshundo regains 14 hit points if the target is a creature.

Arcane Bolt. Ranged Spell Attack: +8 to hit, range 120 ft., one target. Hit:28 (8d6) force damage.

Thundering Blast (Recharge 5–6). Oshundo emits a wave of domineering energy in a 60-foot cone. Each creature in that area must succeed on a DC 16 Intelligence saving throw or take 22 (4d8 + 4) thunder damage and have the stunned condition for 1 minute. A stunned creature can repeat the saving throw at the end of each of its turns, ending the effect on itself on a success.

Reactions

Negate Spell (3/Day). Oshundo targets one creature it can perceive within 60 feet of itself that is casting a spell. If the spell is 3rd level or lower, the spell fails, but any spell slots or charges aren't wasted.

Lore

Oshundo lived in Illithinoch at the height of the mind flayer empire many centuries ago, but Oshundo was driven out for practicing arcane magic. It's obvious that this rejection still stings Oshundo, who refers to Illithinoch's long-dead leaders as "ignorant fools" who are "closed to the flexibility and power of arcane magic."