Her Master was a kind man. He was never 'powerful' in terms of his connection to the Force, but during the Galactic Civil War he had always kept her safe.
Ghen Alturi had made it his purpose to find , protect and conceal children with Force potential. He had been an instructor at the Jedi Academy on Coruscant, and was one of the few living souls that witnessed the aftermath of what a young fallen Jedi named Anakin Skywalker had done to the younglings there. He knew what lay in store for any other such children that 'Lord' Vader might become aware of.
Rhen was an orphan, like countless others living in the innumerable shadows of Coruscant itself. Ghen had found her towards the end of the war and had saved her both from the Empire and the streets.
They were unable to get off world, so he raised her as his own daughter, and taught her what he knew of the Force in secret, in the shadow of the Emperor's throne.
Then one day the Empire 'fell', or rather the Emperor and Lord Vader did. The Empire itself was sundered, broken into multiple factions across the galaxy with no strong leadership after their crushing defeat at Endor. The Rebel Alliance claimed victory, declaring a New Republic, and then with no common foe uniting them, fell back into the petty squabbles and Senatorial schemes that had plagued the Old Republic.
One year to the day after the Battle of Endor, Ghen and his daughter left home to join the celebration of the Battle of Endor. Several muggers followed, and before Ghen could say a word they had stabbed him through the heart with a vibro-blade.
They turned their attention to Rhen, and she felt a dark void open within her. The one bright light in her life was cut down in an instant leaving her alone.
Not alone the Force seemed to promise. Power will keep you company if you only reach out and take it.
Moments later , the body of her erstwhile Master was joined by the bloodied remains of their attackers. The only sound aside from the never ending hum of repulsorlifts high above them was the gentle patter of rain, and the sporadic sizzle of a drop as it landed on her lightsaber.
Her attackers pain and terror was all too brief to sate the hollow of darkness that now grew within her.
She knew in that moment that she would find ways to make herself more powerful, never vulnerable and never weak. She loved Ghen, but the most valuable lesson he taught her was the one at the end: There is no sin worse than weakness. If you are not powerful you will fail those who matter to you most, when it matters most.
She wiped away a tear as she looked at Ghen. She would see that he was properly laid to rest, but only after the one mugger whom she had let live told her who he worked for.
She would ask him many questions.
She would ask him slowly, and before the end he would envy the quick passing of his comrades.
Rhen smiled at the thought.
So how would I represent Rhen in the Cypher system?
Based on her back story 'Vengeful' seems like a good Descriptor and the Adept 'flavored' with Combat that we established previously as the Sith/Jedi type would be her obvious Type.
What about Rhen's focus?
Her origin story emphasizes her desire for power. In the interregnum following the Galactic Civil War, there is no organized Sith or Jedi presence. If she wants to learn and grow her power with the Dark Side, Rhen will need to journey to long abandoned Sith and Jedi temples to acquire lost artifacts such as holocrons.
Furthermore, her whole life has been lived in the shadows up until the murder of Ghen.