SunHi Gavilan arrived in Hathian during her teen years after being abandoned by her biological parents. After becoming homeless and falling in with the wrong crowd, she was adopted by a local cop, Tony Gavilan and a senior HGH physician, Lake Ansar-Gavilan. Life couldn't have been better. She lived in a beautiful home with loving parents and protection and nurturing that she needed. But just as things seemed to improve for SunHi, her life took a sudden turn for the worse. Her mother's affiliation with the Cerberus gang made her a target of the infamous Rejects who made her life and the life of her family and friends a living hell. She wanted revenge, she wanted to make the Rejects disappear. She plotted and acted upon her desires, and with the help of her boyfriend Jin and best friend Paige, she devised a pipe bomb and blew up Piper Rewell's home. But no good deed goes unpunished. The Rejects would have their revenge. She was eventually "taught a lesson" in the way only the Rejects can teach it. Her boyfriend was murdered and her father went missing. After her pregnant mother was tortured and her unborn child murdered, Sun fell into a depression and began to drown out her pain with heroin.

SunHi is known by many as Sun, Sunny or Sunshine and as ironic as those nicknames may seem they have their root in who she use to be before Hathian hardened her. Sun always wanted to do good, help people and make the world a better place. Sounds like the dreams of the average kid; but for her it was something that she lived. On two separate occasions she saved the lives of Hathian citizens. One had been stabbed and Sun employed the first aid techniques taught to her by her her mother's best friend Doe. And on another occasion she happened upon the kidnapping of Dr. Slade, and with the help of her mother Lake rescued her from one of the doctor's psychiatric patients. But if it was said that Sun no longer wanted to help and do good, that would not be true. The truth is that while she does want to make the world a better place, she now doubts that she has the power to do so. She sees the corruption of all around her, even her own mother has done dirt and it saddens and angers her. She is beginning to believe that if you want to change the world, you can't do it with a gentle nudge; but that you must do it with a big and destructive bang.