Semiferum Caste Ophiduan1
This creature appears as a hideous, yet somehow pathetic, cross of man and snake, with a lower body of the latter.

Semiferum Caste Ophiduan (CR 3; XP 800)
CE Medium monstrous humanoid
Init +1; Senses darkvision 60 ft., scent; Perception +8
Defense
AC 21, touch 12, flat-footed 19
(+5 armor, +1 Dex, +1 dodge, +4 natural)
hp 26 (4d10+4)
Fort +2, Ref +5, Will +5
Immune poison; SR 14
Offense
Speed 30 ft.
Melee spiked chain +5 (2d4), bite +0 (1d4 plus poison) or 2 claws +5 (1d4), bite +5 (1d4 plus poison)
Ranged longbow +5 (1d8/x3)
Spell-Like Abilities (CL 3rd; concentration +4)
1/day—charm person (W-DC 12), darkness, hypnotism (W-DC 12)
Statistics
Str 10, Dex 13, Con 12, Int 10, Wis 12, Cha 12
Base Atk +4; CMB +4; CMD 16 (can’t be tripped)
Feats Dodge, Weapon Finesse
Skills Climb +3, Intimidate +8, Perception +8, Stealth +4; ACP -4
Languages Common, Undercommon; speak with serpents
Ecology
Environment jungle, underground
Organization solitary, pair, clutch (3–5), nest (2–5 hominis, 2–13 semiferum, and 2–4 anguineum), or brood (10–80 hominis, 20–160 semiferum, and 10–40 anguineum)
Treasure double (longbow, spiked chain, ophiduan scale, other treasure)
Special Abilities
Poison (Ex) Bite—injury; save DC 13; frequency 1/round for 4 rounds; effect 1d2 Strength; cure 1 save. The save DC is Constitution-based.

The semiferum caste represents the earliest attempts by the anguineum to create an ophiduan/human crossbreed. Unlike their later creations, the hominis, the semiferum are a mongrel combination of traits, far weaker than either their progenitors or their successors. Because they are capable of breeding, however, the semiferum have continued, and today make up a servile underclass of ophiduan society.

Semiferum are often called “snake centaurs” by those who see them but know nothing of their true nature. Their scales cover the same range of colors as those of the hominis, but are usually duller, and often appear slightly sickly. Due to the length of their serpentine tails, semiferum are slightly longer (when stretched out) than tall humans, but do not quite qualify as large creatures. They are roughly 20% taller and heavier than humans.

Ophiduan Characters
The preferred class of the anguineum caste is the antipaladin. The prefered class of the semiferum caste is rogue. The favored class of the hominis caste is cleric who are known to worship the New Gods: Fenris Kul, Lyvalia, Nise, or Vortain. Although not a preferred class, sorcerers, summoners, and wizards are also quite prevalent among the hominis caste, and very nearly equal clerics in number.