An illithilich, as the name suggests, is - an illithid who has undertaken the rituals to become a lich. Its phylactery is typically a tiny, skull-shaped box, which it wears on its forehead or allows to dangle from its tentacles. A sample illithilich is presented here.
Tsurlanej: Illithilich sorcerer 16; CR 26; Medium undead; HD 8d12 plus 16d12; hp 96; Init +6; Spd 30 ft; AC 22, touch 17, flat-footed 20; Base Atk +14; Grp 15; Atk +18 melee (1d4+1, tentacle) or +17 melee touch (1d8+5, touch) or +18 ranged; Full Atk +18 melee (1d4+1, 4 tentacles) or 4-17/+12 melee touch (1d8+5, touch) or +18/+13 ranged (by spell); SA extract, fear aura, improved grab, mind blast, paralyzing touch, psionics; SQ immunities, telepathy, turn resistance +4, SR 25; AL LE; SV Fort +9, Ref +11, Will +20; Str 12, Dex 14, Con -, Int 21, Wis 19, Cha 29.
Skills and Feats: Craft (alchemy) +24, Bluff +24, Concentration +22, Hide +25, Intimidate +26, Knowledge (arcana) +29, Knowledge (history) +29, Listen +25, Move Silently +25, Search +20, Sense Motive 20, Spellcraft +24, Spot +25; Alertness, Combat Casting, Dodge, Forge Ring, Great Fortitude, Improved Initiative, Lightning Reflexes, Silent Spell, Still Spell, Spell Penetration, Weapon Finesse (tentacle).
Extract (Ex): If Tsurlanej begins its turn with all four tentacles attached and wins a grapple check, it automatically extracts the opponent's brain, instantly killing that creature. This power is useless against constructs, elementals, oozes, plants, and undead. Extraction is not instantly fatal to foes with multiple heads, such as ettins and hydras.
Fear Aura (Su): Any creature of less than 5 HD within a 60-foot radius that looks at Tsurlanej must make a DC 31 Will save or be affected as though by a fear spell (caster level 24th). A creature that successfully saves cannot be affected again by Tsurlanej's aura for 24 hours.
Improved Grab(Ex): To use this ability, Tsurlanej must hit a Small, Medium, or Large creature with its tentacle attack. It can then attempt to start a grapple as a free action without provoking an attack of opportunity. If it wins the grapple check, it establishes a hold and attaches the tentacle to the opponent's head. Tsurlanej can grab a Huge or larger creature, but only if it can somehow reach the foe's head. If Tsurlanej begins its turn with at least one tentacle attached, it can try to attach its remaining tentacles with a single grapple check. The opponent can escape with a single successful grapple check or an Escape Artist check, but Tsurlanej gets a +2 circumstance bonus for every tentacle that was attached at the beginning of the opponent's turn.
Mind Blast (Sp): Once per day, Tsurlaiiej can produce a mind blast in a cone 40 feet long. Anyone caught in this area must succeed on a DC 19 Will save or be stunned for 1d4 rounds. The save DC is Charisma-based. This ability is the equivalent of a 4th-level spell.
Paralyzing Touch (Su): Any living creature that Tsurlanej hits with its touch attack must make a DC 31 Fortitude save or be permanently paralyzed. Remove paralysis or any spell that can remove a curse can free the victim (see the bestow curse spell description). This effect cannot be dispelled. Anyone paralyzed by Tsurlanej seems dead, though a DC 20 Spot check or DC 15 Heal check reveals that the victim is still alive.
Psionics (Sp): 3/day - charm monster, detect thoughts, levitate, suggestion. Caster level 8th; save DC 14 + spell level. The save DCs are Charisma-based.
Immunities (Ex): Tsurlanej has immunity to cold, electricity, polymorph (though it can use polymorph on itself), and mind-affecting attacks.
Telepathy (Su): Tsurlanej can communicate telepathically with any creature within 100-feet that has a language.
Turn Resistance (Ex): Tsurlanej is treated as a 28 HD undead for the purpose of turn, rebuke, command, and bolster attempts.
Spells Known (6/9/8/8/8/8/7/6/4; save DC 19 + spell level): 0 - daze, detect magic, detect poison, disrupt undead, light, prestidigitation, mage hand, open/close, read magic; 1st - feather fall, mage armor, magic missile, ray of enfeeblement, shield; 2nd - blur, darkness, see invisibility, spectral hand, web; 3rd - dispel magic, fly, haste, vampiric touch; 4th - contagion, dimension door, enervation, greater invisibility;. 5th - animate dead, cone of cold, passwall, sending,- 6th - circle of death, disintegrate, mass haste; 7th - finger of death, teleport without error; 8th - polymorph any object.
Possessions: +5 ring of protection, ring of evasion; cloak of Charisma, +6 dimensional shackles, rod of absorption.