Melee debuffer advice

[Therians]

Hello everyone, for the next campaign i intend to build a melee debuffing PC, and wuold like some advice on possibile optimizied builds.
The rest of the party will probably be made of a wizard, a skald(or bard), a ninja(or UC rogue), and inquisitor.
The campaign setting will allow humans only as playable race, and have severe restrictions to all long range teleports and limits on the reliabilty on divinations spells. The setting could involve a lot more of scouting, survival in open landscapes and a lot less dungeon crawling than the typical one from what i understood from the GM.

Some of the options I am thinking of are:
Mesmerist
Spiritualist
Shaman
Fighter

If other classes i didin't mention could fit well the role i'm open to every possibility.

With all of them i would like to pair cornugon smash or similar feats, for the rest the mesmerist has all debuffs built in, the spiritualist is similar but with pet, and I love pet classes, the shaman i find very attractive because like cleric or druid dosen't have spells known but can setup for each day with much flexibilty, and the fighter has insted respect to the spell casting classes less versatility but has probably a more relayable damage output to compensate for the fewer debuff capabilities.

[exelsisxax]

What sources are allowed? If 3.pp, DSP probably has quite a few classes for you in either psionics or path of war.

Don't know why you're including fighter in that list though, it is arguably the worst class that exists for "debuffing" things.

[Psyren]

I know you already mentioned it outside of your list, but Unchained Rogue is an excellent melee debuffer ([Double] Debilitating Injuries, Distracting Attack, Slow Reactions, Crippling Strike, Knockout Blow, unchained poisons etc.)

[Kurald Galain]

There's a debuffer Magus build (www.giantitp.com/forums/showthread.php?423754-Myrrh-Frankincense-and-Steel-Kurald-Galain-s-Guide-to-the-Magus&) that's pretty solid. It works off Frostbite + Rime Spell + Enforcer, basically.

[Therians]

For the Rogue i haven't considerd it much mostly because it may alredy be a choiche for an other party member, even if he wouldn't go debuffing so it could come out pretty diffrent pc's, i will look in to it.

For third party contenet it can be allowed with GM discretion case by case, and as for the fighter it wuold be a choiche more for melee dps and less versatility, but with feats like conrugon smash(coupled with a cruel waepon -4 to everything more or less), dazzling display, disarm, dirty trick and trip, up do dazing assault at level 11 that i find amazing it can actualy hinder the enemy and make them easyer to hit for allies and lower theyr saves. I call that a debuffer, i'm not expert with fighters (usually i play full casters with focus on crow controls) but with the right archetype I think the thing can be even pumped up, the major problem with a figher is how easly he can be disabled (flying out of reach, getting invisible, easy target for save or sucks, difficult terrain crowd controls etc).

[Geddy2112]

Wizards and bards/skalds also do well to debuff.

If you want to be an intimidation style thing, any full BAB martial class can pull off dazzling display or power attack/cornagun smash. The best is arguably the antipaladin, as you can break fear immunity found in a lot of enemies, and give a -4 to saves against fear to the non immune. The antipaladin also has touch of corruption, which stacks on a lot of debuffs in the form of cruelties- you can go shaken into frightened and panicked.

[exelsisxax]

For the Rogue i haven't considerd it much mostly because it may alredy be a choiche for an other party member, even if he wouldn't go debuffing so it could come out pretty diffrent pc's, i will look in to it.

For third party contenet it can be allowed with GM discretion case by case, and as for the fighter it wuold be a choiche more for melee dps and less versatility, but with feats like conrugon smash(coupled with a cruel waepon -4 to everything more or less), dazzling display, disarm, dirty trick and trip, up do dazing assault at level 11 that i find amazing it can actualy hinder the enemy and make them easyer to hit for allies and lower theyr saves. I call that a debuffer, i'm not expert with fighters (usually i play full casters with focus on crow controls) but with the right archetype I think the thing can be even pumped up, the major problem with a figher is how easly he can be disabled (flying out of reach, getting invisible, easy target for save or sucks, difficult terrain crowd controls etc).

If your DM will let you, DSP ultimate psionics has a lot of casters with many control and debuffing powers that you could potentially use. Some at like spells, others less so (personality parasite is hardcore). Path of war has many options for standard condition-based debuffing, usually with damage at the same time. Stalkers can do a good deal of ability damage, warlords can get up to combat maneuver shenanigans, warders can threaten whole rooms with AoOs, etc.

[Therians]

For the third party content i need to ask the GM, but probably could get complicated

The wizard, bard, skald roles are alredy coverd so I will pass on those, the antipaladine aura of cowardice is very sweet, we still havent decided what alignment we want to go with for the party, but if we go on the evil side this is definitly to consider!

The debuffer magus build linked is very solid, and no one at the table ever played a Magus yet so a reason more to try it out!

Tanks for all the advice so far, if someelse has ideas for other classes, or can give me useful suggestions on how to build correctly for the first 4 classes i presented it will be appriciated :)

[Geddy2112]

For the intimidate build:Since you are human, you can be dazzling display'ing off the bat at level 1. Weapon focus+dazzling display. If you go fighter, that is an extra feat for power attack.You eventually want power attack and cornagun smash, and to use the best 2 handed melee weapon you can grab. Dreadful carnage, shatter defenses, disheartening display, and violent display(if your DM allows you to take it because it was intended for weretigers) are great add on's for melee bashing/intimidating.

For shaman, you can also go dazzling display, but you have far nastier debuffs. You want the slumber hex from the witch list ASAP-it is basically a save or die, particularly if the rogue can get a hit in. Evil eye is a bit less useful than misfortune, but it works for a round even if they save against it, and once you stick it you can leave it on with chant. Misfortune is much stronger if it lands, and is chantable. The bones spirit has a hex that inflicts shaken, eventually frightened and panicked. It also has the spells cause fear and fear, but those are on the shaman list already. The slums spirit can trip people at range and deal damage with the accident hex. Shaman's get touch of fatigue as a orison, which is a great touch debuff, and have several other touch based debuffs. While it is not really melee, you can still carry a big weapon, pick all the dazzling display feats, and grab heavy armor proficiency to hold your own. Unless your caster level is critical, I would probably dip fighter for the bonus feat and proficency rather than blowing a feat on it. Or just get by for medium.