I've written her backstory as if in the Forgotten Realms setting. I'm not trying to say we 'should' do that, it just tends to get my creative juices flowing (have DMed, read novels, and played games like Baldur's Gate, in FR). It'd be trivial to substitute or edit out the proper nouns.
Mechanically she's not very damaging right now, but will become better in one level (more sneak attack, swashbuckler's best class feature, and a very strategic feat). In the meantime she can at least be a skillmonkey, specifically scouting, locks, traps, and bluffing.
WotC-style plaintext stat block for now, will do mythweavers later:
Class: Rogue / Swashbuckler
Bio: Daughter to retired adventurers who'd more or less bought their way into polite Luskan society using the treasures, skills, and reputations gleaned from their exploits, Aria grew to found herself nudged towards high learning. Her parents, it seems, hoped for a safer life for their daughter, and to their dismay her favorite subject seemed to be her fencing practice nonetheless. At least, unlike most of her friends' parents, her own seemed amenable to the idea of a daughter learning such things at all, perhaps because their careers had shown them what a dangerous place the world could be.
These teenage tensions boiled over into Aria learning how to sneak out and about at night, and she got herself into tatters of trouble, and eventually one scrap she'd not have survived from herself. Rescued from petty thugs of a Luskan pirate lord by a priestess of the Red Knight, Aria ventured out to visit her savior's temple on subsequent nights. She never lost her disobedient urge, but perhaps channeled it with more purpose.
She found companionship and learning of the sorts she'd longed for, which proved a bulwark against a dark part of her own nature: she discovered through the aggravating throes of puberty, and leafing about in her family heraldry, that one of her great-grandmothers just might've been an erinyes devil. This shared revelation renewed her priestess benefactor's attentions and concerns. So far, Aria has maintained a far loftier heart than her infamous ancestor's. The blood may've even contributed a disciplined and logical bent of mind which serves well one who would revere the Lady of Strategy.
(Will provide more of a 'coda' to backstory when I have a better sense of the RP's opening location/scene, i.e. why and how she got there.) Aria
, lesser tiefling, gestalt rogue 2 swashbuckler 2
Medium Outsider (native)
Hit Dice: 2d10+4 (22 hp)
Speed: 30 ft.
Armor Class: 19 (+5 Dex, +4 armor), touch 15, flat-footed 14
Base Attack/Grapple: +2/+5
Attack: kukri +8 melee (1d4+3/15-20) or comp. longbow +8 ranged (1d8+3/x3)
Full Attack: two kukris +6 melee (1d4+3/15-20) or comp. longbow +8 ranged (1d8+3/x3)
Space/Reach: 5 ft./5 ft.
Special Attacks: lesser darkness 1/day, sneak attack +1d6
Special Qualities: darkvision 60', evasion, grace +1, resistances (cold, elec, fire 2), trapfinding
Saves: Fort +2, Reflex +9, Will +1
Abilities: Str 16, Dex 20, Con 14, Int 16, Wis 13, Cha 9
Skills: Bluff +6, Disable Device +8, Hide +12, Listen +6, Move Silently +10, Open Lock +10, Search +8, Spot +6, Tumble +10
Feats: Improved Critical (kukri), Telling Blow, Two-Weapon Fighting, Weapon Finesse
Alignment: Lawful good
Deity: Red Knight ('The Lady of Strategy', LN goddess of tactical and wisdom warfare) if Forgotten Realms setting; or closest analog of Athena if in another setting
Flaws: Frail (-1 hp/level), Weak Fortitude (-3 Fort)
Languages: Common, Draconic, Elven, Infernal, Sylvan
Possession: two mw kukris, mw comp. longbow (Str rating +2), mw chain shirt, quiver with 100 cold iron arrows and 20 silver arrows, 2 kukris, 2 throwing axes, 2 light hammers, 6 daggers, grappling hook and 100' of silk rope, thin bedroll and rain tarp, one tenday of rations, flint and tinder, 3 sunrods, two scout's outfits, one silk aristocratic gown, forest camouflage rain cloak (mw tool for hide), soft padded elven footwear (mw tool for move silently), map of the known world, canteen, light warhorse and military saddle, 100 gp
Darkvision (Ex): A tiefling has darkvision to a 60-foot range.
Lesser Darkness (Sp): Once per day, the tiefling may use an effect similar to darkness (caster level equals tiefling's character level), except that the radius is 5 feet. This ability is the equivalent of a 1st-level spell.
Skill Bonuses: A tiefling has a +2 racial bonus on Bluff and Hide checks.
Resistances (Ex): A tiefling starts play with resistance 2 to cold, electricity, and fire.
Telling Blow (Ex): add sneak attack damage to critical hits.
Sources: Complete Warrior: swashbuckler; PHBII: Telling Blow; Savage Progressions (Wizards site): lesser tiefling (i.e. LA +0 tiefling)