Okay, I wanted to do something a little different with my Heka, so for one, I had them wield 50 size-appropriate Greatswords, each held in two hands, which dramatically increases their damage output. The I added U_K's Warmonger ability, since it fits so well. Then I added their Insight bonus to a wider array of stats. Finally, and this is more for my setting (as they're outfitted in the armories of the Stellar Void) they're equipped with powerful epic armor and weapons inlaid with orichalcum.
They're obviously the most powerful of the abominations, I honestly think their CR may still be low considering how much damage they can deal out. (Average 10,000/round or so against a non-crit-immune opponent, and that's without Power Attack.). Though, at this point, d100 hit dice are starting to crop up, so it's not that much of a stretch. There are other way to defend against pure melee anyways. They might even be a little over-CR'd in that case.
Immortal Hekatonkeires
Huge Outsider (Chaotic, Evil, Extra-Planar)
Hit Dice: 104d20 +2,704 +104 (4,888 hp)
Initiative: +45 (+13 Dexterity, +4 Divine, +20 Insight, +8 Superior Initiative)
Speed: 100 ft., Fly 300 ft.
Armor Class: 165 (-2 Size, +52 Armor, +16 Deflection, +13 Dexterity, +4 Divine, +20 Insight, +52 Natural)
Flat-Footed: 152 Touch: 61
Base Attack/Grapple: +104/+166
Space/Reach: 15 ft./15 ft.
Attack: 50 Huge +6 Orichalcum-Inlaid Great Swords +166 10d10+67 15-20/x4
Special Abilities: Summon Hecatonkeires
Special Qualities: Abomination Traits, Constant Insight, Critical Hit Immunity, Divine Toughness, DR 50/--, Electricity Immunity, Fast Healing 50, Regeneration 50, Superior Multi-Weapon Fighting, SR 118, Telepathy, Warmonger
Saves: Fort +109 Ref +99 Will +86
Abilities: Str 71 Dex 27 Con 63 Int 18 Wis 16 Cha 42
Skills: Climb +161, Diplomacy +144, Hide +140, Intimidate +144, Jump +161, Knowledge (Religion, the Planes) +135, Listen +184, Search +185, Sense Motive +134, Spot+184, Survival +157
Feats: Cleave, Combat Reflexes, Great Cleave, Greater Weapon Focus (Great Sword), Greater Weapon Specialization (Greater Sword), Improved Critical (Greatsword), Improved Initiative, Melee Weapon Mastery (Slashing), Power Attack, Improved Sunder, Weapon Focus (Great Sword), Weapon Specialization (Great Sword)
Epic Feats: Dire Charge, Epic Weapon Focus (Great Sword), Epic Weapon Specialization (Great Sword), Heavy Armor Mastery, Improved Combat Reflexes, Improved Critical Multiplier (Great Sword), Improved Toughness, Greater Critical (Great Sword), Greater Critical Multiplier (Great Sword), Greater Power Attack, Greater Sunder, Light Armor Mastery, Light Eradication, Medium Armor Mastery, Multi-Weapon Rend, Perfect Cleave, Perfect Sunder, Power Attack mastery, Superior Cleave, Superior Initiative, Uncanny Power Attack, Weapon Abatement
Alignment: Chaotic Evil
Environment: Divine Necropoleis, Temporal Prisons
ECL: 153
CR: 102
Possessions: 50 +6 Orichalcum-Inlaid Huge Great Swords, +20 Heavy Fortification Orichalcum-Inlaid Full Plate
Combat
Cleave
A Hekatonkeires may take a 5 ft. step between Cleave attacks and Cleaves on Critical Hits in addition to when it drops a foe.
Constant Insight
Hekatonkeires gain a +20 Insight Bonus to Armor Class, Attack Rolls, Initiative, Saving Throws, and Skill Checks.
Divine Toughness
Hekatonkeires have d20 hit dice.
Immunities
Hekatonkeires are immune to Ability Damage, Ability Drain, Critical Hits, Death by Massive Damage, Electricity Damage, Energy Drain, and spells from the Enchantment, Illusion, and Transmutation schools.
Multi-Weapon Rend
Whenever a Hekatonkeires succeeds on two successful attacks against an opponent, it Rends them for 20d10+82 damage. It may only Rend an opponent once per round, but may an unlimited number of opponents per round.
Power Attack
Hekatonkeires Power Attack at a 4:1 ratio and automatically Power Attack for the amount by which their Attack Rolls exceeds their opponent’s Armor Class.
Sunder
Hekatonkeires deal triple damage on Sunder attacks.
Summon Hekatonkeires
Once per day, a Hekatonkeires may summon another of its kind.
Superior Multi-Weapon Fighting
Hekatonkeires fight with 50 Great Swords simultaneously (each held in two hands) with no penalty. While flying, it may bring all its attacks to bear by spinning around in mid-air, otherwise, it may only bring 5 attacks to bear against a Small opponent, 10 against a Medium opponent, 15 against a Large opponent, and 30 against a Huge or lager opponent while fighting on the ground.
Telepathy
Hekatonkeires may communicate telepathically with any creature within 1,000 ft. that has a language.
Warmonger
Hekatonkeires may select feats normally available only to Fighters.
They're obviously the most powerful of the abominations, I honestly think their CR may still be low considering how much damage they can deal out. (Average 10,000/round or so against a non-crit-immune opponent, and that's without Power Attack.). Though, at this point, d100 hit dice are starting to crop up, so it's not that much of a stretch. There are other way to defend against pure melee anyways. They might even be a little over-CR'd in that case.
Immortal Hekatonkeires
Huge Outsider (Chaotic, Evil, Extra-Planar)
Hit Dice: 104d20 +2,704 +104 (4,888 hp)
Initiative: +45 (+13 Dexterity, +4 Divine, +20 Insight, +8 Superior Initiative)
Speed: 100 ft., Fly 300 ft.
Armor Class: 165 (-2 Size, +52 Armor, +16 Deflection, +13 Dexterity, +4 Divine, +20 Insight, +52 Natural)
Flat-Footed: 152 Touch: 61
Base Attack/Grapple: +104/+166
Space/Reach: 15 ft./15 ft.
Attack: 50 Huge +6 Orichalcum-Inlaid Great Swords +166 10d10+67 15-20/x4
Special Abilities: Summon Hecatonkeires
Special Qualities: Abomination Traits, Constant Insight, Critical Hit Immunity, Divine Toughness, DR 50/--, Electricity Immunity, Fast Healing 50, Regeneration 50, Superior Multi-Weapon Fighting, SR 118, Telepathy, Warmonger
Saves: Fort +109 Ref +99 Will +86
Abilities: Str 71 Dex 27 Con 63 Int 18 Wis 16 Cha 42
Skills: Climb +161, Diplomacy +144, Hide +140, Intimidate +144, Jump +161, Knowledge (Religion, the Planes) +135, Listen +184, Search +185, Sense Motive +134, Spot+184, Survival +157
Feats: Cleave, Combat Reflexes, Great Cleave, Greater Weapon Focus (Great Sword), Greater Weapon Specialization (Greater Sword), Improved Critical (Greatsword), Improved Initiative, Melee Weapon Mastery (Slashing), Power Attack, Improved Sunder, Weapon Focus (Great Sword), Weapon Specialization (Great Sword)
Epic Feats: Dire Charge, Epic Weapon Focus (Great Sword), Epic Weapon Specialization (Great Sword), Heavy Armor Mastery, Improved Combat Reflexes, Improved Critical Multiplier (Great Sword), Improved Toughness, Greater Critical (Great Sword), Greater Critical Multiplier (Great Sword), Greater Power Attack, Greater Sunder, Light Armor Mastery, Light Eradication, Medium Armor Mastery, Multi-Weapon Rend, Perfect Cleave, Perfect Sunder, Power Attack mastery, Superior Cleave, Superior Initiative, Uncanny Power Attack, Weapon Abatement
Alignment: Chaotic Evil
Environment: Divine Necropoleis, Temporal Prisons
ECL: 153
CR: 102
Possessions: 50 +6 Orichalcum-Inlaid Huge Great Swords, +20 Heavy Fortification Orichalcum-Inlaid Full Plate
Combat
Cleave
A Hekatonkeires may take a 5 ft. step between Cleave attacks and Cleaves on Critical Hits in addition to when it drops a foe.
Constant Insight
Hekatonkeires gain a +20 Insight Bonus to Armor Class, Attack Rolls, Initiative, Saving Throws, and Skill Checks.
Divine Toughness
Hekatonkeires have d20 hit dice.
Immunities
Hekatonkeires are immune to Ability Damage, Ability Drain, Critical Hits, Death by Massive Damage, Electricity Damage, Energy Drain, and spells from the Enchantment, Illusion, and Transmutation schools.
Multi-Weapon Rend
Whenever a Hekatonkeires succeeds on two successful attacks against an opponent, it Rends them for 20d10+82 damage. It may only Rend an opponent once per round, but may an unlimited number of opponents per round.
Power Attack
Hekatonkeires Power Attack at a 4:1 ratio and automatically Power Attack for the amount by which their Attack Rolls exceeds their opponent’s Armor Class.
Sunder
Hekatonkeires deal triple damage on Sunder attacks.
Summon Hekatonkeires
Once per day, a Hekatonkeires may summon another of its kind.
Superior Multi-Weapon Fighting
Hekatonkeires fight with 50 Great Swords simultaneously (each held in two hands) with no penalty. While flying, it may bring all its attacks to bear by spinning around in mid-air, otherwise, it may only bring 5 attacks to bear against a Small opponent, 10 against a Medium opponent, 15 against a Large opponent, and 30 against a Huge or lager opponent while fighting on the ground.
Telepathy
Hekatonkeires may communicate telepathically with any creature within 1,000 ft. that has a language.
Warmonger
Hekatonkeires may select feats normally available only to Fighters.