Problem with Vexing Dodger (Limb-Climber)

[Rioko Ray]

Limb-Climber (Ex)
When adjacent to or in the space of a corporeal creature at least one size category larger than herself, a vexing dodger can climb that creature’s body with a successful Climb check against a DC equal to the target creature’s CMD. Although the vexing dodger is holding on to the creature, this action isn’t a grapple; it doesn’t provoke attacks of opportunity from the creature, and neither the vexing dodger nor the creature she climbs gains the grappled condition. While the vexing dodger is on the climbed creature, the creature takes a penalty on attack rolls against the vexing dodger equal to the number of sneak attack dice the dodger possesses.

This ability replaces trapfinding.

Improved Dirty Trick (Ex)
At 2nd level, a vexing dodger gains Improved Dirty Trick as a bonus feat, even if she doesn’t meet the prerequisites.

This ability replaces the rogue talent gained at 2nd level.

Underfoot Agility (Ex)
At 3rd level, a vexing dodger gains a +1 morale bonus on Acrobatics, Climb, and Escape Artist attempts against creatures at least one size category larger than herself. This bonus increases by 1 for every 3 levels beyond 3rd.

This ability replaces trap sense.

Underfoot Trickster (Ex)
At 4th level, a vexing dodger can move through the space of a creature two size categories larger than herself without needing to attempt an Acrobatics check. She would still need to succeed at Acrobatics checks to avoid attacks of opportunity provoked by leaving a threatened space; this ability covers only the ability to move. Additionally, whenever the vexing dodger hits a larger foe with a melee sneak attack, she can choose to forgo the sneak attack bonus damage and instead attempt make a dirty trick combat maneuver as a swift action.

This ability replaces uncanny dodge.

Distracting Climber (Ex)
At 8th level, when a vexing dodger attempts a dirty trick maneuver against a creature she’s climbing, she gets a bonus on the combat maneuver check equal to the number of sneak attack dice she has.

If she chooses to sicken the target with her dirty trick and succeeds at her combat maneuver check, the target must succeed at a Fortitude saving throw (DC = 10 + 1/2 the vexing dodger’s level + her Intelligence modifier) or be nauseated for 1 round.

How exactly "Limb-Climber" feature of Vexing Dodger works?
И тело вопроса что-то вроде. "Limb Climber" is not very well explained. It is not a one-sided grapple similar to stirges and the like (it says so in text), so how exactly does it work? If I am climbing a creature, do I move with the creature? When I am climbing, am I positioned in creature's space or adjacent to it? Do I provide flanking if I am climbing in it's space? If I do not move with the creature, do I just kinda drop at the space I am if it moves away? If I move with the creature, how can it stop me from climbing it? Is it some kind of CMB check, should it try to bullrush me or something? I've looked at similar climbing mechanic on Kaiju, but it's not elaborated there too

[Sir Longears]

You are right that this ability isn't well explained. Very interesting and flavorful, but it leaves a lot of doubts. As far as I know, there are no FAQs or clarification on the matter, so in the end it will be one of those "talk to the GM" abilities. It is so poorly defined that it is also difficult to even go for the usual RAW vs. RAI thinking.

From your all your questions, the only one that is very clear is that you do not flank while sharing the enemy's space unless you have an ability that says this (like the swashbuckler's mouser archetype).

I, personally, could see this ability working in two ways, one very simple and another more complex.

Limb-Climber (light): You see most of this as fluff, getting exactly what the ability says and nothing more or less. While adjacent to the target, you make a Climb check vs. the target's CMD and if you succeed, the target gets a penalty to attacks. It costs you no action, you do not move into the target's square, you don't move with the target and "fall off" if they do. You ignore the climbing rules and just focus on the simple idea of making a check and getting a benefit if you succeed. You spend very little on this, there are no major drawbacks neither for you nor for the opponent and it is also very easy for the enemy to get rid of you. IMO, this seems fair.

Limb-Climber (heavy): Climbing is generally part of a move action and since the ability doesn't say otherwise, this is still the case so it will cost you a move action. This doesn't provoke from your target and considering you aren't actually leaving your space, you should not provoke from others. If you fail by less than 4, nothing happens. If you fail by 5 or more you might take some damage and end up prone (but that is unlikely since you are just starting the climb), so you might want to consider being good at Acrobatics as well (which you probably are as a rogue).

You'll need both your hands free to climb, so if you are planning on attacking your enemy you'll need the a natural attack, unarmed strike or the Quick Draw feat, and when doing so, you'll be able to use only a single hand because the other will be constantly clinging to the enemy.

While climbing, you'll lose your Dex to your AC unless you have a climb speed or an anility that says otherwise.

Great, now you are climbing on your enemy! You do not move into their space and remains adjacent to them, flanking it applicable. You might move to other adjacent spaces by using further climb checks and spending more move actions, though you will provoke AOOs. If the enemy moves, you move with them and they get to choose your new position since they can turn around as much as they want. Since this could be considered forced movement, you should not provoke AOOs thanks to this. If the enemy moves and this would put you in dangerous position, you might be allowed to release as a free action outside of your turn, and if there is no room for you in their new position, you might be forced into releasing and staying on the last possible legal position.

To stop you from climbing them, the enemy could attack you, since whenever you take any damage you need another Climb check to avoid falling. The DC of this check should be the enemy's CMD. Likewise if you are moved away from your enemy, you also fall off, and this can be done through multiple combat maneuvers (bull-rush, drag, grapple, reposition).

So, all things considered, in terms of actions, it costs you a move action, but costs the enemy a standard action to remove you (most likely) and unlike Dirty Trick, the penalty you apply will not wear off on its own. It scales pretty well, but at higher levels CMDs tend to skyrocked, so you'll be forced to expend a lot of resources to keep you Climb skill on par.

The need of Quick Draw is a pain and the loss of Dex to AC is huge, specially for a Dex-based class like the rogue, even if not that difficult to overcome (the Scrambling Servant trait does this). You also can't use TWF, usually a great option for rogues), so you'r damage will suffer. Against smart enemies, this would be very risky for they could move you into precarious situations. All in all, also seems pretty fair IMO.

[Rioko Ray]

The hard option seems pretty interesting but makes the ability too expensive. To get a small advantage, you spend a huge amount of everything. I trade a full attack for a chance to get a small bonus. Getting heaps of fines and a chance to fall. Since at a high level the opponents have a fairly large СMB, it will not be difficult for them to get rid of my. Which makes the ability more harmful than useful.

We agreed DM, to use the first option but with the condition that I spend a quick action. Since this archetype gets a bonus for dirty tricks by climbing on an opponent. And the archetype can activate a dirty trick with a quick action. I'll have to decide whether I want to get the climbing bonus or use a dirty trick.

[Mysterious Stranger]

You are not climbing in the creatures space you are climbing the creature. If you climb a moving object like a wagon or ships rigging you move with the object. If not sailing a ship becomes incredibly dangerous. Therefor you move with the creature.

When in doubt about whether two characters flank an opponent in the middle, trace an imaginary line between the two attackers' centers. If the line passes through opposite borders of the opponent's space (including corners of those borders), then the opponent is flanked.

Since you are occupying the same square the line only crosses one border of the opponent’s space. That mean you do not flank the creature.

To remove a climbing creature, you can use several combat maneuvers. Any combat maneuver that moves the character should work. So, bull rush, drag, reposition or trip can free you. While neither the climber nor the target is grappled nothing prevents the target from grappling the climber. A successful grapple will also mean the target can no longer climb. Doing any of these may provoke an attack of opportunity from the climber if the target does not have the improved version of the relevant feat.