Beast master build

[Falcon X]

We are about to play a one-shot game using level 7-10 characters, and one of the players wants to play something with the flavor of a beast master.

I want to emphasize that I'm not going for optimization. I'm even okay if it takes a hit. The important thing is the flavor of the character.

I'd be open to any creative ideas. I'm going to assume the base class will be either Druid or ranger, maybe a spirit shaman.
I'm looking at flavor such as:
- Shapeshifting/wild shape. Could be into a single form or many forms. Multiple forms of a similar archetype might be ideal.
- at least one animal or spirit animal companion.
- personality traits in tune with a beast or beasts.
- working with or casting spells that get creatures to do the work for him.

Please post basic build ideas. Though, if you just point me towards prestige classes, spells, items, feats, etc that fit, I can put them together if need be. Thanks!

[Flickerdart]

Straight Druid is pretty great for this. There really aren't any PrCs or dips that progress both wildshape and animal companion.

Here are some other options:
Divine Minion: Wild Shape as an 11th level druid into one of several pre-set animal forms. LA+1 template.
Entomanothrope: Like a lycanthrope, but for vermin. Notable is their ability to command twice their HD in vermin - if vermin are close enough to an animal, an entomanothrope can both be one and command two.
Wild Cohort: A feat that gives any character a Druid's animal companion, but weaker.
Beastmaster PrC: Multiple animal companions, progressively weaker. Pick up Natural Bond to increase the effective level; this is a good class if you started as Ranger but still want a companion.
Master of Many Forms: Good at turning into stuff, not much else.
Master Transmogrifist: An arcanist's take on this whole thing. Augments Polymorph in various weird ways. Combine with Improved Familiar for a Winter Wolf or something.

[Falcon X]

Good thoughts, and I might still go vanilla Druid.
Some things just matter that he has it rather than if it progresses well. Might take a dip for an animal companion or such for its own sake. Though your feat might do the trick.

Some things you said I might play around with:
- a vermin lord. If I'm correct, there is a prestige class that goes with this. Could be fun
- beast master sounds neat, playing off several companions.
- I might play around with spirit shaman a little. I like the idea of a spirit guide. Not required though... And I could work it into the flavor of others if I wanted to.

[Flickerdart]

- a vermin lord. If I'm correct, there is a prestige class that goes with this. Could be fun
There is, but you need 4th level spells to get in.

[ranagrande]

I'd go with something like Bard 3/Ranger 1/Spirit Shaman 1/Abolisher 1/Beast Heart Adept 1

Take the Fey Bard variant from Unearthed Arcana and get the Obtain Familiar feat.

You've got an animal companion, a familiar, a monstrous companion, a spirit guide, and wildshape. And you're an excellent skillmonkey to boot.

[eggynack]

I'd go with straight druid, and as your source of animal friends, you should pick up initiate of nature from player's guide to faerun. It's a lot less obtrusive and also a lot less stupid than beastmaster, and you can use it to pick up a good range of animal densities. Of course, this is also backed up by the normal animal companion, and a high quantity of summoning.

For the rest of the build, I've always been a fan of a somewhat good focused desert half-orc with half-orc substitution levels from races of destiny. The substitution levels naturally give you an edge within this concept, with your animal companion gaining toughness, and with the ability to use your strength score for wild empathy bolstered by the typically high strength score of wild shape forms. For the good half, you're usually going to want to pick up exalted companion from the book of exalted deeds anyway, to give the companion vow of poverty, and from that point I tend to think it makes sense to use broader theming, either going all the way with personal vow of poverty, halfway with lion of talisid, or a bit of the way with exalted wild shape.

[thethird]

Suplementing the druid suggestions shifter druid might be of interest, they get a spirit companion in exchange of their animal companion that they can use to possess themselves and buff themselves or the animals that they summon.

Shifter Druid / Moonspeaker is a good option.

For permanent animal companions I would consider Initiate of Nature and Wild Cohort, both already mentioned.