"Flicker", the Ghost, OR The Vanishing Twin Blades Strike Swiftly

"Flicker" is another of the Bloody Blade assassins, and the second most powerful active member (Ox being the most powerful).
She was created when someone needed to break the line of devils that was holding Ox and the other assassins at bay; she materialized, as if from nowhere, to gut a devil, her invisibility only temporarily dispelled.
She is a mysterious woman, though less so than Ox. Which is ironic, considering the fact that she can turn invisible at will, an aftereffect of being killed by a ghost, and improperly raised.
Flicker was adopted by the previous head of the Bloody Blades. He trained her from a young age into a weapon, his left hand, while her brother (two years old) was his right. All the other trainees had failed, and died, or so Flicker and her brother were told.
Flicker suffered a brutal childhood. She didn't have any chance to play, to enjoy, being constantly sent to kill others.
And then, one day, she died.
A mission went sour, and she was killed by the target's bodyguard, the ghost of the former general.
And then, she woke up. Her body was tingling, and sightly wrong. Her flesh felt cold, and numb, and damp. And, when she looked at her hands, she was translucent.
Next she looked up, into her brother's rage filled face. With a solemn nod, he replaced his mask, and turned back to the matter at hand.
It was only later that she would learn of how her father had forbid any attempts to rescue her, how her brother had rebelled, how the two had fought and her brother had won, and how her brother had, in his rage, leveled the castle that she had fallen in, but for the one staircase to the room they had interred her in.
Now, Flicker serves her brother, no less demanding a master, but a kinder one (though her brother's time on The Throne has begun warping him into a reflection of their erstwhile father.
Flicker works side-by-side with Ox on most missions, helping to end threats to the Bloody Blades before they begin, and taking on only the most difficult of contracts.
The numbness, cold, and dampness, the trademark signs of invisibility (in my game settings), have never really left her alone, leading her to take more and more risks, all in search of that high, that thrill, that sensation of being alive.
As such, she ends up dead more often than not, and each time her brother's non-standard, cheating resurrection spells bring her back, more and more of her slips away into the void. (This also accounts for why she is so low-level comparatively, when she has been training since she was three)

“Flicker” Human Rogue 10 CR 11

Init +5    Senses S/L +14/+14 Darkvision   Languages: Common, Dwarven, Goblin

Defenses AC 18 (+3 dex, +5 armour) Will +6   Ref +12   Fort +7

HP 57 (10d6+20)  

Speed 30 ft

Melee:

Cold Iron Longsword +14 (1d8+6+1d4 Vile/19-20)

Silvered Longsword +14 (1d8+5+1d4 Vile/19-20)

Charge: Cold Iron Longsword +14 (1d8+8+1d4 Vile/19-20) and Silvered Longsword (1d8+7+1d4 Vile/19-20)

Cold Iron Longsword +12 (1d8+6+1d4 Vile/19-20) and Silvered Longsword +12 (1d8+5+1d4 Vile/19-20) and Cold Iron Longsword +7 (1d8+6+1d4 Vile/19-20) Silvered Longsword +7 (1d8+5+1d4 Vile/19-20)

Ranged:

Hand Crossbow +12 (1d4/19-20+poison)

Base attack +7     grp +12

Special actions: Sneak Attack +5d6, Dual Strike, Two Weapon Fighting, invisibility

Special abilities: Improved Evasion, Evasion, Improved Uncanny Dodge, trapfinding, trap sense +3

Abilities   STR 20  DEX 20  CON 15  INT 15  WIS 13  CHA 10

Feats(5): Two Weapon Fighting, Oversized Two-Weapon Fighting, Improved Two-Weapon Fighting, Dual Strike, Weapon Focus (longsword)

Skills: Bluff +13, Hide +18, Move Silently +18, Climb +18, Search +15, Disable Device +15, Open Lock +18, Spot +14, Listen +14, Tumble +18, Balance +18

Equipment: “Tooth” +1 blackflame cold iron Longsword, “Claw” “+1 blackflame silvered longsword, +2 studded leather, +2 cloak of resistance, boots of springing and striding

SLA:

• At will - detect magic, detect scrying, detect secret doors, invisibility

Design Notes:

Flicker has invisibility and the detect spells at will because of her (repeated) brush(es) with death. Her brother's resurrection spells are not quite standard, which leave her closer and closer to fading into the stream of magic that governs the world. Her invisiblity has always been an issue, ever since that first raising, when she partly fused with the essence of the ghost that had killed her. The numbness, the cold, the dampness, the signs of an invisibility spell, have never truly left her alone.