Next up is the sentinel. Here's what we know about it from the game:
Str 10, Dex 10, Con 10, Int 13, Wis 13, Cha 10
AC 2
40 HP
No resistances
No eye rays, but has monster summon I, II, and III, and animal summon I, II, and III.
As usual, we'll use Krishnath's suggested HD (5d8).
Here's the stat block:
Beholderkin, Sentinel
Small Aberration
Hit Dice: 5d8+15 (37 hp)
Initiative: +2
Speed: 5 ft. (1 square), fly 20 ft. (good)
Armor Class: 18 (+1 size, +2 Dex, +5 natural), touch 13, flat-footed 16
Base Attack/Grapple: +3/-3
Attack: Bite +2 melee (2d4-2)
Full Attack: Bite +2 melee (2d4-2)
Space/Reach: 5 ft./5 ft.
Special Attacks: Summon creature
Special Qualities: All-around vision, darkvision 60 ft., flight
Saves: Fort +4, Ref +3, Will +7
Abilities: Str 6, Dex 14, Con 16, Int 17, Wis 17, Cha 15
Skills: Concentration +11, Hide +14, Knowledge (arcana) +11, Listen +5, Search +15, Spot +17, Survival +3 (+5 following tracks)
Feats: Alertness (B), Augment Summoning, Spell Focus (Conjuration)
Environment: Cold hills and underground
Organization: Solitary, pair, or cluster (3-6)
Challenge Rating: 5
Treasure: Standard
Alignment: Usually lawful evil
Advancement: 6-10 HD (Medium); 11-15 HD (Large)
Level Adjustment: --
A 3-foot wide orb floats in midair. It bears a large central, and numerous smaller eyes dot its body. The smaller eyes vary in apperance, some seem like cats' eyes, others like those of reptiles, some like those of fish, and some of more alien origin.
Sentinels are mutant beholderkin created by Lycanth the Enlightented, a powerful wizard in the service of the dragon Abazigal. Because sentinels are created via experimentation on standard beholderkin, true beholders and their kin will attack them on sight.
A sentinel is a 3-foot wide orb dominated by a central eye. Numerous smaller eyes cover its body, each appearing to have come from a different species of creature. Unlike many beholderkin, its central eye serves no special function.
Sentinels speak the language of Beholders, Common, Abyssal and Infernal.
Combat
Sentinels generally prefer to summon creatures to do their fighting for them, staying back and playing the role of commander and tactician. They use their bite attacks only as a last resort.
Summon Creature (Sp): Once per round, a sentinel can summon any creature on the summon monster III or summon nature's ally III lists with automatic success. Alternatively, the sentinel may summon 1d3 2nd-level creatures of the same kind, or 1d4+1 1st-level creatures of the same kind. Summoned creatures may appear anywhere within 60 feet of the sentinel. This ability is the equivalent of a 3rd-level spell.
All-Around Vision (Ex): Sentinels are exceptionally alert and circumspect. Their many eyes give them a +4 racial bonus on Spot and Search checks, and they can't be flanked.
Flight (Ex): A sentinel's body is naturally buoyant. This buoyancy allows it to fly at a speed of 20 feet. This buoyancy also grants it a permanent feather fall effect (as the spell) with personal range.
The sentinel first appeared in the Black Isle computer game Baldurs Gate II: Throne of Bhaal, (2001).