My players in my Kingmaker group are one member short of a full group, so I've been letting them have a swappable NPC companion roam with them to fill out a full party, choosable from any NPC they get up to helpful disposition that feels like traveling with them for a while (although only ever one at a time). I'm leveling these NPCs up with the party to remain relevant, but building them weaker to avoid stealing their spotlight: the real PCs are 20pt buy, the NPCs are 15pt buy (or for non-standard races, like the captured centaur or Garuum the boggard, the usual "add pc levels to the race with a level adjustment of the CR" and the +4, +4, +2, 0, -2 stat adjustment from the bestiary), the PCs have three traits, the upgradable NPCs will only have two, and the NPCs will only have heroic NPC gear instead of PC gear.
So far it's mostly been Mikmek (whom I've made a bolt ace) and Jhod will be available when they reach his level, as they just finished his temple quest and made him quite happy. But the PCs made friends with Tyg and Perlivash, and upon seeing his picture and learning about how he liked to sit in hats and do loops in the air, etc, the party oracle (and future Baroness, and girlfriend of the party's de facto leader) squealed and said she "totally wants one!" Needless to say, I'm thinking Mikmek might take a hike for Perlivash soon.
I'm wondering how I should advance him. The ideas are either draconic or fey or crossblooded both sorcerer, or increasing racial HD.
The rules for adding class levels are pretty simple to understand, and from what I can understand by reading Nyressia's stat blocks in book 6, it seems class levels add to natural spellcasting, so I am guessing a level of sorcerer would make him a 4th level caster, given his three racial HD, and otherwise have the effects of a first level sorcerer in regard to bloodline, etc. (Please let me know if I'm wrong about that.)
Alternatively, and preferably if it works like I think, I would add racial HD. It wouldn't come with the attribute bonuses adding class levels does, or simplicity, but I'm wondering if it will increase his basic abilities. The problems with that are a) I don't want to increase his size. It ruins his cuteness. The bestiary rules do say you can ignore that side effect. b) The HD increasing rules don't say it affects your spellcasting. If it doesn't, I'd like to stick with class levels for him, but if it does, I think this option is better. c) Does it affect the formula for his breath weapon DC? I think it's a nice ability, but the usefulness will drop with level if it doesn't scale. Most similar abilities go off of HD or 1/2 HD, but his entry only specifies that it is Con based.
I know as the GM I could hand-wave all of this, but I'm trying to make it a specific power level...worthy of joining them, but not outshining. (All his spells, for example, will probably remain nonlethal deterrent type stuff to remain part of his personality and theme).
If anyone can help answer these questions or offer suggestions, I'd appreciate it.
I'm also tagging this in the Homebrew subforum of the Pathfinder RPG section in case that is more appropriate.
So...no actual opinions?
Another option would be to see if there's a way for the oracle to gain a familiar. I played an Arcanist during kingmaker and took Perlivash as my familiar at level 7.
Other than that sorcerer levels are probably the way to go. They advance his casting and let him stay off of the front lines.Unfortunately the breath weapon is based on racial hit die and would become nigh useless.
Since he is a dragon adding racial hit die would increasing his casting levels and spells available but as I know of there's no hard rules for advancing a faerie dragon so its up to you to figure out when he would get what. Looking at true dragons should provide a basic outline of when he could get certain abilities but any spell-casting he gets from added racial hit die wouldn't hold a candle to what he would get from class levels.
Honestly, I'd give him the sorcerer levels with the fey bloodline. It's much more simple to do it that way. And yes, each level of sorcerer would increase his base caster level.
This was something I'd wondered about, as well. Based on the dragon age rules, I'd advance him an effective age category for every two additional hit dice, which will add +1 round to the duration of his euphoria breath, bump up his stats, and add 2 to his sorc level.
1) as to the familiar suggestion, the oracle would require a three-feat investment to pull that off (skill focus, eldrich heritage, and improved familiar) That's a loooooooooooing time to wait, and a heavy investment to put in when they already as a group have a floating NPC they can swap out.
2) The problems with adding class levels are the attribute bonus that monsters with class levels usually seems balanced, like with boggards or centaur or whatnot, but faerie dragons have pretty high stats for such a low CR even without the +4/4/2/2/0/-2 you get to toss in there. Furthermore, the monsters as PCs section recommends using CR as a guide for level adjustment, with a gradual removal of one LA per three class levels, but given spellcasting stacks with Dragon HD and sorcerer levels, that leads to an obscenely powerful spellcaster, as CR is 2 with HD3.
3) I like Kenderkin and Carbide's ideas, they're kinda similar to what I was thinking: Use HD as level (Dragon HD is too powerful not to), add spellcasting with levels, at +1 to DC of breath weapon every 2 HD, effective caster level for SLA gone up with HD. No bloodline or other non-spellcasting sorcerer benefits.
Does that seem balanced? Too strong, given how awesome Dragon HD is (full BAB, d12 hp, all good saves)? Too weak? (Doubtful) Would increasing breath duration, spell resistance, or other racial abilities with HD be overkill? I don't want this little guy to grow more powerful than the PCs as they level up together.
Here I did an un-optimized DMPC few years ago using a Pseudodragon and not a Faerie Dragon, I don't know if it could help you with advancing Perlivash, but it was a very fun and effective helper and not a Mary Sue to mine party.