Regarding http://te4.org/games/addons/tome/fated-beta :

Just got finished doing a bit of in-depth testing of a new tree (not uploaded, as of writing), and I realized that the class could actually use a bit of a guide.

Birth

The obvious first question is race-- and the obvious answer is Halfling. Starting bonus to Luck, Cunning, and Dexterity; save bonus racial.

Other decent options are Dwarf, Cornac and Thalore.

As far as creating your character? The starting points aren't always the best place to put your points (in discussion with Fayd about that right now). Steal Luck isn't so useful until you actually get a way to spend your fortune. Felicity is a great tree (if you want to go that route), and it's not supposed to be unlearnable-- but it is. My bad :)

The temptation when playing a class from an add-on is to rush to their special talents. With Wyrdthieves, that just doesn't work. Their special talents don't shine until later levels-- they certainly won't keep you alive long enough to reach higher levels! The good old rogue stand-bys are the way to go for your early levels. A starting character cannot afford to ignore Lethality, Dual Weapons, or Dual Techniques, and that's where your beginning points should go. These are your offensive melee options, and they're essential.

Weapons

With the talents you can learn, and the places you need to put your points, there aren't really any options besides dual wielding daggers. That's the only way you're going to be able to do decent damage.

Infusions

A couple of good regen infusions are good for starting out, but you'll probably want to replace them with shielding runes ASAP. A teleportation rune is also essential. Wild infusions are great-- you haven't got much in the way of status clears or immunities.

Escorts

Arcane all the way baby. They'll always give you good stats. If you happen to get an early Temporal Explorer, there's nothing wrong with a free point in Dreamwalk though. Since you don't have any natural mana regeneration, you're better off avoiding any of the spells.

Luck and Fortune

Several Wyrdthief abilities debuff an opponents Luck and add it your own Fortune. Your Fortune has pretty obvious effects-- it's how you spend your talents, it affects the strength of various passives such as those from Felicity. Many talents exist that scale with your Fortune: often, these talents can become detriments when your Fortune is below its midpoint. Talents in the Disaster tree actually scale with your bad Fortune, which means that they typically have no effect when you Fortune is above its midpoint, and the most dramatic effects when your Fortune is zero.

It's easy to miss the effects of the Luck debuff. Luck affects Defense, Accuracy, Crit Rate and Damage, Ranged Defense, and Trap avoidance-- all of the the things that Felicity affects. Fayd's model was to have your extra fortune (above the midpoint) give 1/6 of a point of luck via each talent point in each tree of Felicity. (That's no longer the case for Turn the Tables, which got nerfed to be in line with other crit bonuses.) So remember, every time you debuff an enemy's Luck, you're doing something significant and useful.

Felicity vs Disaster

You've got two choices, and they're largely incompatible. With Felicity, you get large passive bonuses that scale with your Fortune-- something that means you'll want to keep your Fortune in the top quarter of the bar, because those bonuses can go negative when your Fortune drops below its midpoint. With Disaster, you've got free Fortune whenever you're below your midpoint, but your goal is to spend your Fortune as quickly as possible, so that you debuff your opponents for larger amounts! These builds aren't totally incompatible-- a bit of Bad News can be a nice insurance policy for your Fortune, and you don't need low Fortune to benefit from an Unlucky Streak, but for the most part, you'll want to decide whether to play Felicitously or Disastrously at the beginning of your game, and stick to that.

With Disaster, it's worth remembering that almost all of the talents scale with both your bad Fortune and your bad Luck. Bad Luck is handled a little strangely-- it bends the curve. So if you're at 0 fortune, it doesn't matter what your luck is, you'll get the same scalar. But at, say, the bottom quartile of Fortune, your Luck can have a large effect on these talents' scaling.

Talents

A lot of Wyrdthief trees aren't totally obvious at first. Let's go over the talents specific to them.

Certainty

Okay, so this one is obvious. It's worth noting that increased talent level reduces the cooldown as well as the duration and number of effects.

Denied

This is going to be essential at lower levels. When all of your opponents are melee attackers, Denied can nicely fill in the spaces between regeneration infusion or shield runes, giving you the few extra turns of melee invulnerability that you need to have a shot at killing Bill the Troll (no Certainty in that prospect stated or implied).

Vetoed

This is one that needs a little thinking about. Guaranteed saves? What's not to like? Well, how about the fact that an awful lot of attacks don't actually grant any saves. Or the fact that it's ridiculously hard to predict which turns you're going to need to save against effects. Vetoed is a great ability, but it's hard to use.

Guaranteed

Who doesn't love guaranteed criticals? Use with Unlucky For Some to get a good starting boost to your Unlucky Streak.

Destined

+ 2/+2 to useful stats. Great. Non-diminishing returns, worth taking to five, if you feel like pursuing Certainty.

Thievery

Steal Luck

If you're playing a Felicitous build, this is your source of Fortune. If you're playing a Disaster build, this is your source of luck debuff. Either way: you don't need Steal Luck at level 1, but you're going to need it by level 50. As long as you're doing that, why not invest a few extra points to get the bonus damage?

Steal Weapon

Depending on when you gain it, an AoE disarm can be incredibly effective, or pretty blah.

Steal Heart

This is your summon. One less bad guy to worry about, one more for your opponents to worry about. Don't bother to use it on skeletons or mummies (or elites). And watch out for the death explosion. It uses your spellpower against their mental save, so you're going to need some Magic to make it work.

Steal Life

For a melee build, this is essential. The damage bonus is large, and you're going to need the heals. For Felicitous builds, watch out for the rapidity with which it drains your Fortune; for Disastrous builds, watch out for it running out of Fortune and terminating!

Grace

A Felicitous line with a couple of great escapes.

Serendipity

Make them hit themselves when they miss you? Sure, why not. Considering the potential Defense of a felicitous build, this is a great way to chew through melee attackers.

Dance with Destiny

A lightweight movement infusion, combined with a passive move bonus, this is where Grace starts to be specific to Felicitous builds. The passive bonus is randomly applied, and there's no way to predict whether you'll benefit from it on any given turn, but it can be extremely powerful-- and at low Fortune, extremely detrimental.

Caution

A bit of insurance on your Stealth is never a bad thing-- but even if you're not improving Stealth, you'll probably want a point in this to reach the next talent:

Now You See Me

A great escape. Phase door combined with invisibility means that even if you don't land where you wanted, you'll have a good chance of getting away (especially when followed with Dance with Destiny!). This ability is useful enough that even Disastrous builds might be willing to accept the penalties of Dance with Destiny.

Grand Larceny

Definitely maybe. While this gives you some powerful AoEs, you're likely to benefit more from mastery of one of your existing talents. (Which is largely because talent points mostly give linear returns, which is partly my fault...)

Heist

Steal Luck on a different cooldown, with an AoE. Great for Felicitous or Disastrous builds.

Sticky Fingers

Can end up giving a tremendous amount of gold-- that you can turn in for Big Prizes in Last Hope. Probably not the best talent in the line, but a decent one nonetheless. Don't bother trying to farm-- the Developers have done everything they can to discourage this behavior :)

Steal Armor

Not an AoE, but a tremendous resistance debuff. Frequently nothing but a waste of Fortune, but in the case where you need resistances debuffed, nothing else comes close.

Spontaneous Combustion

Short lived, highly damaging DoT, with a damage type few can resist.

Dealer

All of these talents require decks to use. That's not as much of a drawback as it might seem-- given the egos on decks, you might just want to be wearing one anyways.

Hit Me

This isn't enough damage to be overpowering-- it's a little bit extra, at low levels, but it scales with the level of your deck, and with your dexterity, and pretty linearly with talent level, because each additional level makes this talent act, not more powerfully, but FASTER. The real point of this ability lies when you start to find some egoed or artifact decks, which can use powerful damage types.

Bluff

Even if you don't want to go any further, this line can be worth pursuing for Bluff, which is something rather like a targeted phase door+trap. Just don't use it on anything too close-- it leaves a trap behind which can damage you.

Underhanded Dealing

This is all about stacking the deck. High talent levels only reduce the Fortune cost and failure rate. If you're a fan of Hit Me, and you see a king on the bottom of your deck-- well, if your top card was a deuce, you've just done six times as much damage. Not to mention the potential value of actually knowing which damage type you're going to be dealing next. But the real power comes when used in conjunction with

Dealers Choice

Massive combo damage for Hit Me. These combos are almost impossible to pull off (without cheating), but if you do, you can expect some of the most obscene damage numbers in the game. Royal Flush? That boss is nearly dead.

Gambler

Where Dealer lacks raw damage, Gambler delivers.

Throw the Bones

Chance of AoE, chance of 100% resistance penetration, large range of (relatively basic) damage types, linear damage scaling. All of that's worth a little bit of risk of self damage.

Snake Eyes

Five turns of DoT is perfectly reasonable for a ranged attack, and a bit of extra damage (at no additional Fortune or energy cost) is always appreciated.

Bad Break

Only for the risk averse-- or those that want the next talent.

Impossibly Lucky

Cheating? Maybe. This is your huge cost, huge payoff ranged ability. AoE, massive damage, complete resistance penetration.

Felicity

Saved for last because it's so fundamental.

Fortuitous

Some reduced fortune cost (which you'll want if you want to pursue the rest of this tree), and an incomparable Defense bonus (that turns into an incomparable Defense penalty at low Fortune). High levels in this talent can render you impervious to melee damage.

Good Graces

And again, incomparable accuracy bonuses (or penalties)-- this talent should be an either/or with Combat Accuracy, because you should never need both.

Charmed Life

The saves are great (and essential, and part of why I recommend Dwarf). The luck bonus is easy to ignore, but Luck raises your base and maximum Fortune in addition to its other effects.

Turn the Tables

If you're going Felicity, go all the way. This gives you awesome critical boosts (again, or penalties), and a chance out of bad Fortune. Just pop the talent and spend spend spend!

Disaster

For the unlucky.

Bearer of Bad News

The movement speed bonus is great (too bad it doesn't stack in any useful way with the bonus from Dance with Destiny). This constantly steals Fortune (and thus debuffs Luck) from all foes within its radius-- but in proportion to how little Fortune you have. It will never take you above your midway point. That makes the Fortune drain a bit of a mixed bag: sure, it's free Fortune, but every bit of Fortune reduces the effectiveness of the luck debuff (and movement speed buff).

Unlucky For Some

So you've got a bit of crit pow buff (scaling with target's bad Luck), but the fun part is the streak. Your crit rate goes up every successive time you crit-- approaching, but never reaching, 100%. So you can potentially take a 2% crit rate up to 100%, without other investment (and if you're careful, can use some Guarantees to get you there). But watch out, because if you ever fail to crit, the streak disappears, and so does your bonus. Note that this is the only talent in the tree that doesn't depend on your own bad Fortune-- worthwhile even for a Felicitous build.

Black Cat

The potential debuffs are pretty large-- global speed penalty, cross-tier effects-- but it's remarkably difficult to use. You can't cross your own path, or you destroy it. You need quite a bit of speed to get your opponent's to cross your path rather than just tracing it to you, and even if you do, you have to be careful that they don't cross it back the other way (which undoes the debuff). But if this is your kind of talent, you can get some serious benefit out of it. (Note that the path duration scales with bad Fortune-- if you're above the midpoint, no path will be made.)

Master of Disaster

Yup, all talents. That includes bump-attack. Anything they do that targets you has a chance of being retargeted to somebody nearby. It decides on a target (from a list weighted by bad luck and distance to you), and then creates a chance based on that target's bad Luck (mostly). So you've got a serious incentive to keep the Luck debuffs as powerful as you can.

Dual Weapons

Dual Weapon Training

Your first point doesn't look very good, but this tree gives, strangely, accelerating returns. 5/5 asap.

Dual Weapon Defense

Part of the reason your Defense can get so high. Mostly, you'll only want this at a low talent level.

Precision

Utterly worthless.

Momentum

Nice talent, but you're unlikely to have the Stamina to maintain it for long.

Dual Techniques

Dual Strike

Pretty essential for the early game.

Flurry

Your main melee damage dealer.

Stealth

Easy to miss. You haven't the health or armor to take many hits. Stealth is a very good idea.

Dirty Fighting

A few more good ways to spend your stamina :)

Lethality

Lethality

A must have. You're probably going to need to raise both your dexterity and your cunning-- but never your Str. But don't feel like you need it at level 1.

Combat Training

Thick Skin

A must have at 5/5; you'll probably require a small arsenal before you can reach the Con requirements.

Armor Training

Fortune is modified by Fatigue mods. You'll probably want to avoid this tree.

Combat Accuracy

Between Good Graces, luck debuffs, and your own naturally high Dexterity, you probably don't need any points in this tree.

Dagger Master

5/5 ASAP.

Suvival

Heightened Senses

Pretty important for a stealth build.