Ulitharid (The Black Pits II)

Location

 * In the fifth arena battle of the third tier, a group of mind flayers has to be defeated, which are overseen by a single ulitharid under a Minor Globe of Invulnerability. The creature has many resistances and immunities and can be regarded as invulnerable, but it also doesn't engage in the fight. When the battle's over it will vanish from life and the plane with a last Psionic Blast.