Ok this is what I have for a Fiendish creation
Fiendish Warforged Goliath, Level 10 Fighter
Large Construct(Living Construct, Extraplanar)
Hit Dice: 10d10+50(109 hp)
Initiative: +1
Speed: 30 ft. (6 squares)
Armor Class: 20 (-1 size, +2 natural, +8 armor, +1 Dex), touch 10, flat-footed 19
Base Attack/Grapple: +10/+21
Attack: Greathammer +17 melee (3d6+12/x4)
Full Attack: Greathammer +17/+12 (3d6+12/x4)
Space/Reach: 10 ft./10 ft.
Special Attacks: Smite Good 1/day
Special Qulaities: DR 5/magic and adamantine, Darkvision 60 ft., SR 15, fire and cold resistance 10, Living Construct traits
Saves: Fort +12, Ref +4, Will +2
Abilities: Str 24, Dex 12, Con 20, Int 12, Wis 8, Cha 6
Skills: Climb +20, Intimidate +11, Jump +20
Feats: Adamantine Body, Improved Damage Reduction x3, Exoctic Weapon Proficiency(Greathammer), Weapon Focus(Great Hammer), Weapon Specialization(Greathammer), Power Attack, Improved Bull Rush, Knockback
Environment: Underground
Organization: Solitary, pair
Challenge Rating: 13
Treasure: Standard
Alignment: Usually Chaotic Evil
Advancment: By character class
Level Adjustment: --
So, what do you think. I'll probably make a Draconic, Half- Fiend, and Half Dragon one as well.