Alright, so, I find myself slightly confused with the Serpent's Fang power.
Serpent’s Fang (Ex): At 1st level, you can grow fangs as a free action. These fangs are treated as a natural weapon inflicting 1d4 points of damage plus your Strength modifier (1d3 if you are Small) plus poison (Bite—injury; save Fort DC 10 + 1/2 your sorcerer level + your Constitution modifier; frequency 1/round for 6 rounds; effect 1 Con damage; cure 1 save). At 5th level, these fangs are considered magical for the purpose of overcoming DR and the poison damage increases to 1d2 Con. At 7th level, your poison requires 2 successful saves to cure. At 11th level, your poison damage increases to 1d4 Con. You can use your fangs for a number of rounds per day equal to 3 + your Charisma modifier.
Now, I know creature poisons are based off of Con, but pretty much every Sorcerer special attack power I have seen (I've read them all) uses Charisma. The ones that don't change the primary ability for Sorcs that is. Even the Envenomed Wildblood's poison is Charisma based.
Envenom (Su): At 3rd level, as a swift action, you can lick or bite a melee weapon to imbue it with 1 dose of black adder venom. The poison’s DC is equal to 10 + 1/2 your sorcerer level + your Charisma modifier. You may use this ability once per day at 3rd level, and one additional time per day for every three additional levels. The poison cannot be removed or stored, and the weapon loses the benefit of the poison after the first successful attack or 1 hour has passed.
The bloodline power replaces serpentfriend.
So is this a case of copy-paste-edit typo, or is this seriously constitution based? I mean hell, even Avalanche from the Shaitan Bloodline is charisma based (hit someone with a damaging spell, bull rush them with a CMB of caster level + cha mod).
Serpent's Fang seems to be an (Ex) ability rather than (Su), the poison is also much more dangerous dealing con damage and does have duration based on charisma. I dont think it is an error rather a design choice, but having it as an (Ex) ability seems weird since the fangs dont grow naturally I'd think, it should be (Ex and Su) in my opinion at least.