22 years ago - Karu-Sil is born to Citadel Colonists.
8 years ago - 14-year-old Karu-Sil is lost in the wilderness of a new planet. She is possessed by the planet's native spirit-beasts, tears off her own lips to more resemble her new pack.
6 years ago - 16-year-old Karu-Sil is found by her colony and kills all of them. Assumed the soul survivor, she is rescued and place in a recovery facility buy the Green Lantern Corp. She & her ghost-pack murder her caretakers. She is locked on Oa while they attempt to find a way to seperate her.
5 years ago - 17-year-old Karu-Sil is moved off-planet to Citadel prison in anticipation of Hal Jordan's attack by the Green Lantern Corp.
3 years ago - 19-year-old Karu-Sil & Arkillo are freed from Citadel prison by Amon Sur to become one of Thaal Sinestro's lieutenants, armed with a simplified version of Sinestro's yellow ring.
1 year ago - 21-year-old Karu-Sil & Thaal Sinestro's forces battle the reunited Green Lantern Corp. She is finally seperated from the spirit-beasts during the battle and is left catatonic.
The mid 2000's saw a gigantic explosion of supporting characters in the Green Lantern mythos as the world grew by leaps and bounds. At the time it was interesting to read, but in hindsight a lot of the developments of the era clash with the overall flavor of the Green Lantern story, so we're leaving almost all of it by the wayside. There are a few characters we're bringing along in one capacity or another, however, and Karu-Sil is one of them.
Karu-Sil's Comic History
Karu-Sil first appeared in 2005 during Geoff John's Sinestro War storyarc, one of the dozens of characters built to fill out the pages depicting the new Sinestro Corp. She was among the characters who generated enough interest to have her backstory told in it's own short, but from there on she would continue to primarily be featured in the group shots of the Sinestro Corp.
Of course, there are plenty of appearances over the years that gave her a larger role to play, but these largely came after the fact. The main thing she brought to the table was a very particular look and a way of executing her powers that was just unique enough when compared to other ring weilders that made her stand out.
Our Karu-Sil Story
I've gone on in a lot of places about why we're not actually using the Sinestro Corp or other non-green corps in our timeline (diminishing the importance of the original corp, an over-reliance on cannon-fodder characters, etc). While Sinestro simply wouldn't ever share his power like that (nor COULD he, since he doesnt have a central power battery), there is absolutely a place for him to have lieutenants. He would certainly grant a few trusted warriors a fraction of his power just so they can operate in space and whantnot, leaving them to battle using their own power.
Karu-Sil creates a fun challenge in that her powers are essentially spectral in nature, tied to the creatures she bonded with. If we just give that quality to the creatures originally, then she can already be generating the spectral beasts on her own before she ever aquired a ring. There's something really fantastically monsterous about this character and she'll be a really cool addition to the storyarc that includes Sinestro's lieutenants.