Let's not take too many. I'm taking 3.

*Dwarf hearts in centaur blood
*A jar of dire rat blood
*Duergar hearts in Aether

Hm. So, the result is clearly some kind of dwarf. Centaur blood sounds like strength or speed. Dire rat blood is digging, dexterity, stealth, as are duergar. Aether could be all kinds of things, could be alchemy, could be ethereal. In any case, a kind of stealth creature.

Ak-Karva

Created by the Duergar as shock-troops in their subterranean wars, especially against other dwarves, the Ak-Karva is a horribly mutated creature, combining an equine leg and lower body, wickedly curved claws and a muzzled face only vaguely recognizeable as humanoid.

Ak-Karva

Medium monstrous humanoid (dwarf)
4d8+8 (26 hp)
Initiative +6
Speed: 50 ft., Burrow 20 ft.
Armor class: 18 (+2 dex, +2 natural, +4 armour (chain shirt))
Base attack/grapple: +5/+5
Attack: Claw +5 (1d4+1)
Full attack: 2 claws +5 (1d4+1)
Special attacks: Phase claw
Special Qualities: Darkvision 120 ft, duergar traits, Phase jump, spell-like abilities, Scent (30 ft.)
Saves: Fort +3, Ref +6, Will +4
Str 13, Dex 15, Con 14, Int 8, Wis 10, Cha 4
Skills: Hide +5, Move silently +9, Listen +3, Spot +3
Feats: Improved Initiative, Weapon Focus: claw
Challenge rating: 3-ish?

Phase claw (su): once per minute, as a swift action, the Ak-Karva can channel its ethereal powers into its claws, making them phase through even the toughest armor. Until the end of its turn, all attacks made with its claws are resolved as touch attacks.

Phase jump (su): As a move action, the Ak-Karva can become ethereal to move through obstacles. This allows the Ak-Karva, as part of the same move action, to move up to 30 ft., while ethereal, before become corporeal again.

Duergar traits:
Immunity to paralysis, phantasms, and poison.
+2 racial bonus on saves against spells and spell-like abilities.
Light Sensitivity: Ak-karva are dazzled in bright sunlight or within the radius of a daylight spell.
+4 racial bonus on Move Silently checks.
+1 racial bonus on Listen and Spot checks.
Stonecunning, armor movement (as a dwarf)
Ak-karva do not gain stability

Spell-like abilities:
1/day: invisibility, blink. 3/day: disguise self (dwarf or duergar only)