1. Blade Demon - monster

Has four arms and two legs. Is generally humanoid in appearance, but signficantly light-built and with extremely elongated limbs (about 4 feets both legs and arms). Torso is triangular in shape, with reallsy thin waist (about a foot) and wide shoulders (about three feet). Has a long (about 6') whip-like tail.
They aren't smart or wise, but when it comes to fight they're near genial.
Looks like a man in full plate. In fact, it is just a exoskeleton like a scorpio has, which provide a +10 natural AC bonus. Also he has a +5 AC bonus for high dexterity.
He fight with four scimitars simultaneously. In fact, these aren't real but just projection of his will, invoced in combat only. Consider they are +1, but strike as magical weapon +3.
AlignmentCG, and keeps the word given
SizeMedium (6'6"-7' tall; 150-200 lbs weight)
HD10d10+30 (d12, no less than 3 per die, +1 from Con)
AbilitiesStr 11, Dex 20, Con 12, Int 8, Wis 8, Cha 13
Init+9 (+5 Dex, +4 Improved Initiative)
FeatsImproved Initiative, Expertize, Multidexterity, Multi-Weapon fighting, Improved Multi-Weapon Fighting, Improved Multidexterity; Weapon Focus (Scimitar), Weapon Finesse (Scimitar), Weapon Specialization (Scimitar), Improved Critical (Scimitar), Multi-Weapon Finesse (Scimitar), Improved Finesse (Scimitar)
Attacks4x+17, 4x+12; Slashing 1d6+3, Critical 15-20/x2
AC25 (+5 Dex, +10 Natural)
Base Move50'
SavesFort +8, Ref +11, Will +6
SR15
Damage Reduction*/5 (vs. EVERYTHING without exceptions)
ProgressionSR=5+HD, DR=*/(HD/2), Base attack: HD+2+Dex; +1 Dex per 4HD;
13HD - scimitars are +2 and strike as +4, 16HD - +3 and strike as +5/artifact;
Base Move: 15HD - 60', 20HD - 70'.

Improved Ambi-/Multi-Dexterity: To say that creature uses both hands equally well is something close to lie, because he in fact he "really well uses both hands". That means two (N for N-handed creatures) attacks at highest base attack bonus at no penalty and with full Strength bonus to damage with each hand. Also that means that creature has full number of attacks with all hands.

Two-/Multi-Weapon Finesse: Can fence with two (or more) weapons simultaneoulsy using Dex modifier. Must have a Weapon Finesse with all weapons to be used and then can take Two-Weapon Finesse with each pair (Multi-Weapon with each combination).

Fightlust (this similiar to Berserk): When in fight, Blade Demon comes in specific trans-alike state of mind. In this state he gains +5 bonus to all saves and 2 temporary hp per HD. To get out of this he must succeed with Will save at DC equal to 10 +2 per each full power of two of killed opponents' HD (that is, 12 for 2HD slain, 14 for 4HD, 16 for 8HD, etc). Success means that Blade Demon can stop fight and retreat, failure means that fight will to be continued. DC is increased by 1 for every 10 hp that were lost by Blade Demon. When Blade Demon in such state runs out of victims he can attack friends, if they are closer than five rounds of fast run (after running about that Blade Demon calms enough to distinguish friends from foes).

Improved Finesse:Having Focus and Finesse with a weapon, the one can take this feat, which allows to STAK modifiers from both Strength and Dexterity.

2. Demoniac itself

It's a warrior which is somewhat obsessed about demons. Why - is question of roleplaying, but that is. He is obsessed. Is it that he view them behind each tree, or inside him, or inside others - does not matters. What matters, that he wants to become one of them - to be able to withstand them, or to be adopted as one of them, or to infiltrate their plans or just because they're powerful - any way, he WILL be one of them. And soon.
He fights like a demon, he feared by enemies and his friends are cautious with him, but he wants it to be the way it is - the way to became a demon.
Basic
HDd1040
WeaponsOnly one chosen1
ArmorSpecial*10
Skill Pts215
SkillsAs fighter10
AlignChaotic-5
AttackAs Fighter50
SavesFort+Ref25
Subtotal146
Special
HurtLow-level spell10
FearModerate spell15
Damage ReductionModerate ability10
Fair JumpExcellent ability15
Feats840
Subtotal75
Requirements
Base Attack Bonus +5-12.5
Ambidexterity, Improved Initiative, Expertize-15
Demonic ObsessionJust play it out!
Grand Total (rounded down)208

Lvl Att Saves Special
Fort Ref Will
1+1+2+2+0Hurt, Chooses Weapon
2+2+3+3+0Fear, Weapon Focus
3+3+3+3+1AC+2, Weapon Finesse
4+4/+0+4+4+1Fair Jump, Weapon Specialization
5+5/+1+4+4+1AC+4, Improved Two-Weapon Fighting
6+6/+2+5+5+2Dex +2, Two-Weapon Finesse
7+7/+3+5+5+2AC+6, Improved Ambidexterity
8+8/+4/+0+6+6+2Damage Reduction */2, Improved Critical
9+9/+5/+1+6+6+3AC+8, Improved Finesse
10+10/+6/+2+7+7+3Becames a Blade Demon (+4 Dex, -2 Int&Wis)

Hurt: Can hurt one victim for d6 hp, +1d6 per two levels, upto a 1+Con times per day, plus one at each third level (4, 7, 10). Range - 30', +10 feet per level.

Fear: Can cause fear in a cone of 10*level feet long and 5*level feet wide at far end upto a 1+Con times per day, plus one at 6th and 10th levels. DC to save equals 10+Dex+Level.

Fair Jump: can teleport at will to anybody who has struck him with ranged weapon at the end of round when struck. Unlimited.

Feats: If, by some occasion, Demoniac already has a feat given at his level, he can choose any feat from available as fighter bonus feats.

AC: Demoniac can wear medium and light armor, but from level 5 he is limited to only light armor, and from level 8 he cannot wear any armor anymore. That is because he want to be a demon, and demon don't wear armor!

Dak the TFI