Please take a look at the below and let me have your thoughts. I haven't GMed a Legend campaign, as yet, so have no real frame of reference as to whether or not this version of an Aboleth is powerful, or not. I really quite like the wikipedia description and will probably use that:
Aboleth
Dice Average 1d20 Hit Locations AP/HP
STR 4D6+6 20 1-10 Body 2/12
CON 3D6+1 12 11-12 Tentacle 1 2/12
SIZ 6D6+24 45 13-14 Tentacle 2 2/12
INT 4D6+1 15 15-16 Tentacle 3 2/12
POW 4D6+3 17 17-18 Tentacle 4 2/12
DEX 3D6+1 12 19-20 Head 2/12
CHA 4D6+3 17
Combat Actions: 3
Damage Modifier: +2D6
Traits: Darksight up to 20 m, Tough Hide (2 AP, with no armour penalty), Poison (Mucus Cloud), Poison: Slime
Magic Points: 17
Movement: 16m (swim), 3m (crawl/slither)
Strike Rank: +14
Skills: Athletics 65%, Evade 65%, Influence 90%, Language (Aboleth) 100%, Language (Aklo) 95%, Language (Aquan) 95, Language (Undercommon) 95%, Lore(Arcane) 95%, Lore(The Oceans) 95%, Manipulation 100%, Perception 95%, Persistence 95%, Resilience 75%, Sorcery 100% (Aboleth), Stealth 75%, Swim 100%
Spell-like Abilities: Entrancing Glow, Illusion, Phantasm (Sight), Phantasm (Sound), Dominate (Humans), Dominate (Marine Animals)
Combat Styles: Bite 80%, Tentacle 75%
Poison: Aura mucus cloud (2 metres)
While underwater, an aboleth exudes a cloud of transparent slime. All creatures adjacent to an aboleth are affected.
Application: Contact
Onset time: Immediate
Duration: On-going as long as exposure remains.
Resistance Time: The victim must succeed a Resistance roll each round or lose the ability to breathe air (but gain the ability to breathe water) for 3 hours. Renewed contact with an aboleth’s mucus cloud and failing another save extends the effect for another 3 hours.
Success indicates the victim has resisted the mucus for the remainder of the encounter.
Potency: 95
Resistance: Resilience.
Conditions: Water Breathing. If the victim fails the Resistance roll he loses the ability to breathe air but is able to breathe water for a 3 hour period. This condition is cumulative based on the number of times exposed to the mucus cloud.
Potentially, the Asphyxiation condition could come in to effect.
Antidote/Cure: There is no known method, save magic, that can counteract the effects.
Poison: Slime
A creature hit by an aboleth’s tentacle must succeed on a Resilience roll or have his skin and flesh transform into a clear, slimy membrane over the course of a few rounds. The creature’s new “flesh” is soft and tender, reducing its CON for as long as the condition persists.
Application: Contact
Onset time: Immediate
Duration: On-going as long as exposure remains.
Resistance Time: If the creature’s flesh isn’t kept moist, it dries quickly and the victim takes 1d6 points of damage every 10 minutes.
Success indicates the victim has resisted the Slime once only, a new Resilience roll is required after each successive strike
Potency: 95
Resistance: Resilience.
Conditions: CON Reduced by 4 for as long as the condition persists. Additional damage to area afflicted applies if not kept moist – Apply the Agony condition, as per the Legend Rule Book.
Antidote/Cure: There is no known method, save magic, that can counteract the effects.
Weapons
Type Size Reach Damage AP/HP
Bite M T 2D4
Tentacles L H (5m) 1d6+5 plus slime As per tentacle