[3.5] Adding HD To Familiars

[Thurbane]

I know a familiar uses it's master's HD for effects, but is there any way for it to gain actual HD, for the purposes of taking feats and skill points?

Arcane Hierophant's Companion Familiar works, but I'm wondering if any options exist for a single classed arcanist?

I'm open to a reasonable amount of cheese, but no 3rd party, PF or homebrew please.

Cheers - T

[Doctor Despair]

Could you polymorph them into a Dusk Giant or Barghest and feed them every once in a while? Not permanent, but has the added bonus that you could select new feats each time they lost and regained feats due to varying HD counts

[CIDE]

Could you polymorph them into a Dusk Giant or Barghest and feed them every once in a while? Not permanent, but has the added bonus that you could select new feats each time they lost and regained feats due to varying HD counts

Technically, If you gain those HD and then polymorph out of the form you no longer have the trait that causes the HD to be lost. RAW, they should remain. Even if you want to nitpick shouldn't a thought bottle also fix that issue?

[MaxiDuRaritry]

Polymorph or metamorphosis it into a humanoid or a giant, then have it contract lycanthropy (or cast the good version of the curse of lycanthropy spell on it).

[ShurikVch]

Well, Dragon Familiar will get some HD on their own - just with some time pass

If you get one of Undead familiars, you may try to use Improved Animation feat (Dragon #298) to give it +1 HD

Awaken Magical Beast - 9th-level Druid spell, which allow to awaken Magical Beasts with Int below 3 as if they were Animals; combine it with Ray of Stupidity to add as much HD as you need; 500 XP cost

[MaxiDuRaritry]

Bards get inspire greatness, which gives anyone who hears it 2 HD. This grants feats and skill ranks (overridden) and ability bonuses, as normal for HD, because it's not specified otherwise.

[Miss Disaster]

Polymorph or metamorphosis it into a humanoid or a giant, then have it contract lycanthropy (or cast the good version of the curse of lycanthropy spell on it).
How exactly would this work? Specifically, using Curse of Lycanthropy to help a Familiar gain HD, then feats ...

[Doctor Despair]

How exactly would this work? Specifically, using Curse of Lycanthropy to help a Familiar gain HD, then feats ...

Lycanthropy confers animal HD.

HD confer feats, among other things.