With the entry requirements of 10 skill ranks and a +3 base attack bonus, a character should typically enter the prestige class shapeshifter (Oriental Adventures 45–6) at level 8 (making the character a whatever 7/shapeshifter 1). As this fine answer explains, Pun-pun can enter way earlier, of course, and the feat Primary Contact (Cityscape 61–2) may reduce the level of entry by 1, and the bard's special ability inspire greatness under laboratory conditions may reduce the level of entry by a further 2.
To go one step further, the Web site Planewalker was granted special permission by Wizards of the Coast to update the Planescape setting to Third Edition. That makes material on the Planewalker site—nominally, anyway—official material, although my understanding is that such material is rarely considered official enough for use by actual PCs in actual campaigns. Nonetheless, ask the DM if the feat Prodigy is available. If it is, the feat Prodigy (Concentration) will see the character's maximum ranks in the the skill Concentration increase to his level +6, allowing easy, 1-step early entry into the prestige class shapeshifter as early as character level 5 (e.g. raccoon dog hengeyokai duskblade 4/shapeshifter 1), without the character needing to be favored in a guild and without the character needing to convince a high-level bard to play inspiring music while the character repeatedly falls into pits.
Finally, for comparison and for fun, I've provided the approach below that doesn't involve the 9th-level Sor/Wiz spell ice assassin [conj] (Frostburn 97–8), the supernatural ability energy charge (Monster Manual III 211), or similar shenanigans but that does require a DM willing to tolerate an extremely convoluted character background and make one ruling in the character's favor.
With an approved convoluted character background, a PC can join the campaign with his character having entered the prestige class shapeshifter at character level 2
Yawon is a level 1 sparrow hengeyokai (Oriental Adventures 10–11) totemist (Magic of Incarnum 29–32) who invests 4 skill points in the skill Concentration and who takes as her level 1 feat Flexible Mind (Dragon #326 80), picking the skills Concentration and Handle Monstrous Spider as the class skills that the feat makes always class skills. (While it's not important to this process, for more on the hilarious skill Handle Monstrous Spider, see here.)
Yawon is told that today is the big day and that she'd better shape the soulmeld blink shirt (MoI 60–1), so she does. (She's heard stories that those who didn't died!)
Yawon visits her village's benefactor, a natural weredire eel hengeyokai… who, as gently as he can, bites her. All it takes for a natural lycanthrope to spread lycanthropy is a hit from the natural lycanthrope's bite (see the supernatural ability curse of lycanthropy (Monster Manual 176)), so it appears the benefactor can bite nonlethally—i.e. suffering a −4 penalty on its attack roll with its bite—to spread its unusual form of lycanthropy without any Oopsy! Murder! Even if the benefactor's bite renders Yawon unconscious, the benefactor can spend a charge from his healing belt (Magic Item Compendium 110) (750 gp; 1 lb.) to, if necessary, restore her to consciousness. Anyway, Yawon fails the Fortitude saving throw against the benefactor's bite—or the second one or the third one—, and she gains immediately the lycanthrope template weredire eel… and, as a result, 6 Hit Dice and at least 12 skill points.
Because the skill Concentration is for Yawon always a class skill via the feat Flexible Mind, she spends 6 of those 12 skill points to increase her ranks in the Concentration skill from 4 to 10. (The maximum number of skill ranks Yawon can have in a class skill is 10 because of her 1 totemist class level + 6 die eel animal Hit Dice +3.) (It doesn't matter how she spends the other skill points.)
Yawon now is ECL 9 (1 (totemist) +6 (dire eel hit dice) +2 (afflicted lycanthrope LA—see MM 178)). She has 0 XP and 1 hour to earn 45,000 XP. Fortunately, the benefactor has laid 12 CR 10 traps, each within 2 min. of his hut and each other. Yawon dashes to the first one. Not having been told what to expect, she finds… another hut. (Dum-dum-DUM!) She enters it, its door shuts and locks, and its walls start closing in! She has but 2 rounds to escape or else she'll be pulverized by the CR 10 crushing room trap (Dungeon Master's Guide 74). O, noes!
Yawon moves to the edge of hut and, using the blink shirt soulmeld, takes a standard action to teleport as far as 20 ft. as if with the 4th-level Sor/Wiz spell dimension door [conj] (Player's Handbook 221) to outside the hut and safety. (The dimension door spell allows a creature to teleport blindly to a designated spot within range therefore so does the blink shirt soulmeld.) Yawon survives the trap and earns 4,050 XP. (Don't blame me! This is what a level 9 character receives for encountering a CR 10 trap (Dungeon Master's Guide 38).) She survives 11 more similar traps over the next 30 min. or so, earning a total of 48,600 XP.
After surviving that twelfth trap, Yawon has earned XP sufficient to gain a level, and she meets the requirements of the prestige class shapeshifter. That is, the requirement of base attack bonus +3 is met from the base attack bonus of her 6 dire eel Hit Dice, the requirement of 10 ranks in the skill Concentration is met due to the feat Flexible Mind (Concentration and Handle Monstrous Spider) and the skill points from the 6 dire eel Hit Dice, and the special requirement of an alternate form is met by her hengeyokai race. Yawon advances a level to become an afflicted weredire eel sparrow hengeyokai totemist 1/shapeshifter 1.
Yawon returns to the benefactor. The benefactor administers to Yawon belladonna so that she can use the benefactor's Heal check result instead of risking rolling a 1 on the saving throw against being cured of lycanthropy by the belladonna. (O, heavens, no, Yawon doesn't want to keep the template weredire eel! Yuck! No offense, Mr. Benefactor.) Yawon succeeds on the saving throw and is cured of her lycanthropy. (See Curing Lycanthropy (MM 178).)
Until this point, so far as I can tell, a patient and thorough player could've had his high-level PC manipulate the campaign so as to create this sort of town: it takes only gathering the benefactor—maybe with the 8th-level Sor/Wiz spell sympathy [ench] (PH 292)—, convincing the benefactor that this chain of events is cool—maybe with the 9th-level Sor/Wiz spell programmed amnesia [ench] (Spell Compendium 162–3), building the traps—maybe with the 5th-level Sor/Wiz spell fabricate [trans] (PH 229) that, by the way, all automatically reset—, and cultivating the belladonna—maybe with the 3rd-level druid spell plant growth [trans] (PH 262), although that's probably overkill. That is, until this point, it's just role-playing and rules.
However, after Yawon loses the template afflicted weredire eel, the DM must intervene. She's now a sparrow hengeyokai totemist 1/shapeshifter 1 who lost everything gained from the weredire eel template—including base attack bonus and skill points—, yet she's already taken the first step on the path of the prestige class shapeshifter. The DM may—like the FAQ does—rule that Yawon loses all the benefits of that level of shapeshifter and can't advance further in that class, or the DM may—like the Dungeon Master's Guide does—rule that Yawon keeps the benefits of that level of shapeshifter and can still advance in that class. As this exercise collapses if the DM rules for the former, this writer assumes the DM rules for the latter. (For more on the controversy surrounding prestige class requirements, see here; for more on the controversy surrounding the FAQ, see here.)
No matter how the DM rules, though, Yawon will still be a level 2 character with 48,600 XP. The Player's Handbook on Experience and Levels says that due to a lone adventure a creature "can advance only one level at a time" (58). With that in mind, the DM may rule that upon losing the weredire eel template, Yawon's XP total immediately drops to 2,999 because
If, for some extraordinary reason, a character’s XP reward from a single adventure would be enough to advance two or more levels at once,… she instead advances one level and gains just enough XP to be 1 XP short of the next level. (ibid.)
(To be clear, a level 2 character becomes level 3 with 3,000 XP.) Alternatively, the DM may—perhaps too generously (as if the DM hasn't been overgenerous already!)—give Yawon the rest of the session (or some other reasonable amount of time—perhaps until she next gains XP) to find something to do with that leftover XP before it'll be forfeit. (Maybe the benefactor has a talisman of transference (Player's Handbook II Web enhancement "Magic Items: Transferring XP Costs") (200 gp; 0.5 lbs.) and could use some help paying for a really XP-intensive magic item?)
Either way, Yawon is a level 2 character who is a sparrow hengeyokai totemist 1/shapeshifter 1 and who can, if the DM sides with the Dungeon Master's Guide, continue advancing in the prestige class shapeshifter.
Issues & Concerns
- Any natural lycanthrope will do if it possesses a size category from Small to Large and if it has an animal form that possesses at least 6 Hit Dice. The writer picked dire eel (Stormwrack 148), but another DM may be more comfortable with the traditional brown bear (Monster Manual 269) or tiger (281–2). As the character won't be keeping the lycanthropy, it only matters for the background.
- No DM will let you do this. I mean, okay, a DM might, but you'll probably be friends with that DM and collaborating with him on his setting in an effort to make this chain of events possible so that, after a few sessions, the two of you can write fan-fiction about Yawon's adventures. (Nothing wrong with that, by the way!) What I mean is that it's highly unlikely that a typical DM who's running a typical campaign will allow this, and attempts at get it approved for the typical campaign will probably be met with curt negatives unless alcohol is involved.
Note: It seems to this reader that early entry into the prestige class shapeshifter shouldn't be that big of a deal in most campaigns. For instance, just taking 11 levels of regular ol' druid gets the character most of the same benefits as early entry into the prestige class shapeshifter plus it gets the character 11 levels of druid spellcasting!