Plunder
The fact it only creates two tiles, one of which in a random direction is not good enough. It needs to be able to create more tiles.

Crashing Waves
I'm not fond of the random chance this skill has. It's not mentioned how far the waves travel either. Does it deal multiple instances of damage if hit by different waves? I'm concerned how ridiculous this could be when it comes to the Riot skill later on.

I think it's best to go back to the drawing board for this. Perhaps a wide-line AoE water skill that creates Pillaged tiles or has some kind of bonus when affecting Pillaged tiles and pushes enemies would be better but still be thematic.

Kindled Hearth
Kinda weird but I don't have a big issue with it other than the duration. 2 is too short, permanent is too long. I think you might want to try 3 or 4 rounds.

Razed Ground
I don't have a problem with this one other than the duration. Being able to knock people into the fire for more damage and burn works with other skills.

Makeshift Barricades
Due to the way Pillaged tiles are created, this is not reliable or useful. I also don't think it's a good idea to have skills for the same kind of thing. Razed Ground also serves as a thing to push enemies into for damage.

Summon Crew
Considering the next skill in the list, this can get silly fast. Even without Riot, I think it's still a recipe for disaster, there needs to be a limit, especially considering we don't know how strong or weak these will be.

I think you should to go back to the drawing board for this skill.

Perhaps something along the lines of a non-Invocation 3M skill that creates 3 Mooks (that don't require Pillaged tiles to be made), they'd still be mostly fodder but they'd also have some kind of ability to create Pillaged tiles too. (Through movement or an active AoE skill)

Riot
This skill is way too random to be helpful but worse is that can be used to cause frankly ridiculous scenarios when paired with the other skills Crashing Waves and Summon Crew.

Your average SL2 battle map is fairly big, I don't recall the exact measurements but I think they're approximately ~20x19. On Average, at Max Rank, this would create 95 tiles. That means ~95 instances of Crashing Waves (most of which wouldn't be doing anything productive and probably not great for the game) and ~95 Mooks from Summon Crew (a lot of people doing nothing and a lot of heartache for the game to process).

Knock Knock, Who's There, Cheap Shot
The damage of all of these options are too low. Knock Knock and Who's There are also slightly too FP hungry for what they are.

Attack Break, Skill Break, Spell Break
These ones are concerning, they're strong and have utterly crippling effects. I'm not keen on having three similar skills, I think you could make the Grudge skills more interesting but beyond that I'll address my further concerns at Grudgebearer.

Shield Wall
I think Shield Wall should simply affect all allies within 1 Range of you, that way we don't need the weird stipulation from Plow Through.

Furthermore, Shield Wall doesn't really list any kind of duration.

I think you could make Shield Wall work by simply making it a "Guard" Skill that also reduces damage from allies within 1 Range.

For instance, let's say I use Shield Wall. The Raider and all allies within 1 Range of him will take 30% less damage. Additionally, actions or effects that would break the Raider's Guard would also break the Shield Wall.

Plow Through
Looks good to me.

Stand Ground
I think it needs to be a little better, especially for 30FP. How about throwing pull prevention to the mix? Knockdown Immunity also would be cool but considering how Grudgebearer works, this might be unwanted.

I don't think there's much point to it having 5 Ranks either, 3 Ranks would do.

Grudgebearer
I'm iffy on this mechanic. I'm assuming using a Grudge skill consumes the Grudges despite nothing stating that and that "Only one Grudge can be added by non-Raider skills at a time" means only one Grudge per applicable non-Raider Skill use.

If that's the case, frequency is a problem. Against a typical opponent, knocking them around might be too easy, Bash is a fairly Momentum effecient way to score Grudges, getting 4 Grudges in 2 Rounds easily enough.

This would mean every 3 Rounds you could throw out a Grudge Skill which stops them from using something like Skills/Spells for 2 Rounds which then lets you build up 4 Grudges again fairly safely, making it difficult to fight against, especially with Knockdown and Cheap Shot to also helping impede them.

On the flipside, if you're against an opponent with Knockback Immunity like Spiked Treads, gaining Grudges is a chore, gaining at best against players 1 per 2 Rounds via knockdowns.

Hard to say what exactly should be done here but I do think it needs some more thought into how it should work.

Flay, Concussive Blow, Dislocate, Hamstring, Bone Breaker
In my opinion, these skills are numerous, lackluster and samey. -5 isn't much of a drop for some stats which really leaves most of them as little more than easy 1 Point pick ups to use for Rampage. I think these could use more thought.

Smash Guard
This skill is fine. Might need some damage to it depending on if or how things are tweaked.

Ravage
Depending on what counts as magical boons, this could be overpowered. Also I don't see the point in making this have 5 Ranks when the odd ranks don't give anything. Might want to make this 3 Ranks or have some kind of other benefit to fill the Ranks.

Rampage
The core skill for this archetype is obscene and doesn't offer much of a downside when built around it. While normally, I'd like the downside as it doesn't make building DEF/RES ideal, we still have to consider Damage Reduction from other classes as an issue.

My other big gripe with this is that being able to churn out 5 Attacks in a round is just too much. Axes are strong weapons, they generally have high Power and offer the second highest critical damage behind daggers, which means they can do a ton of damage with basic attacks. Even more so if you factor in On Hit effects from weapons like Burngada or skills like Elemental Augment.

There doesn't seem like a lot of options when faced against this. Buffing up may not be ideal on a count of Ravage being able to clear some buffs. Guarding or counter damage won't keep them at bay due to Smash Guard. Keeping your distance since they don't have gap closing options while going ham seems smart but that may not spare you either, on a count of access to the Grapple talent allowing them to pin someone down the round prior and then unleash a full combo.