Updated.
Organization: Solitary, kiln (5), or pyre? (10-100)
Pyre's good, I'd add a leader and a few magicians.
Organization: Solitary, kiln (5), or pyre? (10-100 plus 1 ruler plus 1-15 magicians)
Is the leader's arcane spellcasting innate or do they have character class levels? Shall we make the leaders cast spells as wizards or sorcerers?
I favour innate wizard-casting which stacks with any wizard levels they gain, since (a) it says they can develop and change their spells, (b) we won't have to worry about the wizard class's other abilities, like familiars and bonus feats, (c) Infernites are born (or, rather, moulded) with the basic fighting and magical abilities of their caste.
The standard magician has a 1/day
improved phantasmal force SLA plus normal wizardly spellcasting. Maybe CL 4th for a "standard magician", to match the HD?
The ruler is a 10th level magician with a 1/day
"mass plane shift"/"
spelljamming" power. Should we stat it up separately, maybe as a magician with 6 levels of wizard?
Treasure: Standard (non-combustible)?
Alignment: Usually lawful neutral?
Advancement: By character class?
Level Adjustment: +5?
An infernite stands 6 feet tall and weighs x pounds.
That all looks good.
Since they're made out of lava they should be a lot heavier than a fleshy creature - 300 or 400 pounds?
EDIT: Upon reflection, I prefer "Alignment: Always lawful neutral" or "Always lawful, usually neutral" going by passages like "they are more rigid, structured, and single-minded of purpose than any humans", "infernite cultures developed very unyielding structures on turbulent, everchanging worlds" and "the individual infernite has very little freedom of choice, nor does it expect any".