Yuan-Ti PC

[An Enemy Spy]

I'm running a 3.5 campaign with my friend and I wanted to bring in a Yuan-Ti halfblood as a character so I looked in the monster manual to see how to make a PC version of one but all I could find were directions on how to make PC purebloods. What a load! So I beseech thee, oh Playground. How doth though make ability adjustments and the like with half-bloods?
PS: I'm a noob, so you might have to dumb it down.

[Assassin89]

My sources, i.e. Heroforge, state that Yuan-Ti half-bloods have a level adjustment of +5 and 7 Monstrous Humanoid HD.

[An Enemy Spy]

I know that but what I'm looking for is ability adjustments, Auto feats, the works

[ColdSepp]

Stats: Per the MM, subtract 10 from even numbers and 11 from odd, so a Half Blood has:

+5 LA

+4 STR, +2 DEX, +2 CON, +8 WIS, + 8 INT, +6 CHA

7d8 Monstrous HD, which give three feats of your choice, +7 BAB, Good Will +5and Reflex Saves +5, Poor Fort saves +2

+4 Natural Armor

Blind Fight, Alertness as Bonus Feats

Special Attacks: Poison, produce acid, spell-like abilities

Special Qualities: Alternate form, chameleon power, darkvision
60 ft., detect poison, scent, spell resistance 16

2 + INT Mod skills per level, x4 at HD 1

Because of this, a PC could take their first class level at ECL 13.

[Assassin89]

Sorry about that,

Ability Adjustment: +4 Strength, +2 Dexterity, +2 Constitution, +8 Intelligence, +8 Wisdom, +6 Charisma
Base land speed of 30 feet.
+4 Natural Armor bonus.
Natural Weapons: Bite(1d6+ strength modifier),
Darkvision 60 feet.
Automatic Feats: Alertness, Blind-Fight
Spell-like abilities: 3/day - animal trance(DC 12 + charisma modifier), cause fear(DC 11+ charisma modifier), entangle(DC 11+ charisma modifier);
1/day - deeper darkness, neutralize poison, suggestion(DC 13+ charisma modifier).
Spell Resistance equal to 9 + class levels (16 for 7 HD)
Alternate Form(Sp): You can assume the form of a Tiny to Large viper.
Detect Poison(Sp): You have the ability to detect poison as the spell.
Poison(Ex): Injury, Fortitude DC 15, initial and secondary damage 1d6 Con.
Produce Acid(Sp): You can exude acid from your body, dealing 3d6 points
of acid damage to the next creature you touch. If you are grappling or
pinning a foe when using this ability your grasp deals 5d6 points of acid damage.
Chameleon Power(Sp): You can change the coloration of yourself and your
equipment to match your surroundings, granting you a +10 circumstance
bonus on Hide checks.
Scent
Favored Class: Ranger

[Gwyn chan 'r Gwyll]

Oh god... I would suggest you homebrew a lower-ECL PC version...