Champion of Debilitation
Race & Abilities
Muse-Touched Aasimar (+2 Dex, +2 Cha)
Lawful Good
STR:13
DEX: 18
CON: 14
INT: 10
WIS: 12
CHA: 16
Ability Increases from Level: All to Dex
Ability Increases from Items: Belt to Dex, Headband to Cha
Levels & Feats
1st Rogue (Thug) : Power Attack
2nd Rogue (Thug): Rogue Ability (Weapon Focus: Rapier)
3rd Rogue (Thug): Dazzling Display
4th Paladin
5th Paladin Dodge or Accomplished Sneak Attacker (your preference)
6th Rogue (Thug): Rogue Ability (Skill Focus Persuasion)
7th Fighter: Cornugon Smash, Shatter Defenses
8th Fighter: Combat Reflexes
9th Fighter: Seize the Moment
10th Fighter: Improved Critical (Rapier)
11th Fighter: Weapon Specialization (Rapier), Weapon Training (Rapier)
12th Rogue(Thug):
13th Rogue (Thug): Rogue Ability (Combat Feat Critical Focus), Wings Aasimar Only Feat
14th Rogue (Thug):
15th Rogue (Thug): Rogue Ability (your pick), Staggering Critical (Rapier)
Beyond I'm not too sure the options since I haven't hit high level play
Skills
You will be able to max 3 skills all the time and more later. So Persuarion, Trickery, and another of your choice. At level 12+ You can start using excess Rogue skills to flesh out other skills.
Items
Gloves of Dueling: You need 5 levels of fighter for these but they buff your weapon training
Armor / Shield +X: Always favor +X over abilities
Cloak of Resistance +X
Ring of Protection +X
Amulet of Natural Armor +X
Explanation of Build
The first few levels are rough. You are rushing Rogue to 3rd level so that you can get DEX to damage. However you are no worse than a normal rogue. You should also note that currently power attack is bugged where Finesse weapons only get -1 attack +1 damage. Hopefully this is fixed soon.
At 4th-5th level you pick up Paladin. This allows you to equip shields and is a huge buff to your saving throws (+3 Fort/Will + your CHA to all saves). Also, casters start becoming more prevalent around this time so you want those Will saves up. Don't forget, against evil big bad guys SMITE is extrememly powerful. Sure you aren't getting a big level bonus to damage but you are completely negating their DR.
6th level you hop back to Rogue for Debilitating Injury. I pick to lower their AC because your other abilities (see below) will be drastically reducing their attacks. But you still have flexibility.
7th level is the sweet spot where the build fully comes online. Before you are a tanky rogue with decent damage, now you are a debilitating powerhouse. Cornugon Smash means all of your attacks that hit get a free demoralize check. You are likely to succeed being your race bonus and optimized Persuasion. Enemies hit by you will be demoralized (Intimidate), Flat-Footed (Shatter Defenses), Sickened (Thug Brutal Beating), and AC penalized (Debilitating Injury) for a total of -4 Attack, -2 damage, No Dex to AC, -2 AC(-4 AC for you), -4 saving throws, -4 skill/ability checks. In addition, if your persuasion roll high enough they could outright flee in terror (effectively working like a stun with extra attacks due to Attacks of Opportunity).
8th - 11th are Fighter Levels. These are necessary to pick up your Teamwork Feats in addition to Weapon Training. Having Seize the Moment + High Dex means anytime another team member with this feat gets a crit, you get a free attack.
Who is your teamate? When you get Amiri at lvl 1 immediately tuck away her big sword (it's really a sub-optimal weapon) and use a falchion. Also multi-class her with 2-handed fighter and keep her that for a long time. She will still be slightly underpar of a custom built falchion user but it's not a big deal. She should also then get Seize the Moment. She will only get 2 triggers due to her DEX but she is there to help you. At 10th level both of you will have 15-20 critical threat range and multiple attacks. Expect to trigger this teamwork feat a ton!
Weapon Training is good but way better with Gloves of Dueling (which increase it by +2 attack & damage)
12+ and it's all gravy with extra sneak attack damage. Once you get Staggering Critical opponents hit by you could lose their full-round attack (since they can only take a standard or move action).
*note* Now as an alternative you could go STR based for better Persuasion (Due to Intimidating Prowess adding STR to CHA) and overall 2-Handed damage but would lose out on a lot of AC due to no shield and extra attacks from seize the moment due to low DEX.