Sandy was a former Special Forces agent who worked for Home Base, helping them track Bruce Banner. She met Doc Samson in Argentina while on a mission, and unbeknown to him, became pregnant with his child, Ricky. She lived in seclusion with Ricky for eight years until Home Base kidnapped him and framed her for his murder to employ her services.
Major Story Arcs
Return of the Monster
Sandy is executed for the murder of her son, and from there Home Base transferred her consciousness into a superhuman clone. She is then sent by Home Base to find and work with Jink Slater tracking Bruce Banner. Due to the fact that Jink mostly works solo the pair are at each other throats often. Sandy uses the tracker, given to her by Home Base and the pair track Bruce to a dinner. During the ensuing confusion Jink executes Sandy by shooting her in the head. She comes back to life and knocks out Doc Samson, who also tracked Bruce to the same dinner. She then takes the computer taken from Doc and tracks the Hulk to a cabin in the woods.
In the cabin she helps the Hulk change back into Bruce and then explains to him that when she was brought back from the dead the first time she was told that if she'd bring in the Hulk she'd get her son back. She knows that Home Base is most likely lying and wants to side with Bruce.
This is when Jink show up and tries to kill Bruce with a Hulk killing gun but it miss fires and Sandy uses the hidden explosives to blow up the cabin killing Jinks and herself. Bruce buries her body and leaves. This is when Sandy comes back from the dead again.
Transfer of Power
After digging herself out the ground she recovered her old laptop, feed off an old man and a little boy taking some of his lifeforce but also his cancer. She then tracked down Banner but just as she found him he was hit by a car and taken to a woman's apartment to mend him back to health. When the woman left Sandra sneaks in and gave Bruce some of her blood to use to heal his wounds.
This drained Sandra and when the police came to the room they found Banner and apparently dead woman they assumed was the woman who hit Bruce and took him in custody for murder. Sandra later woke up on the morgue. She drains some of the mortician's lifeforce and went to find Banner, again.
This time she saved him from Agent Pratt. Sandra and Banner then made a break for it out of the city. Along the way a car passed with her son Ricki in the back. See this caused Sandra to crash. Then Agent Pratt showed up and made her an offer, Banner's life for Ricki's. Sandra excepted but when she hugged Ricki she knew something was wrong and was unsurprised when Pratt killed the boy. Sandra then distracted Pratt long enough for Banner to change into the Hulk and rip Pratt to pieces.
Later Sandra helped Banner bury Pratt's pieces and then when Banner revealed the the Ricki Pratt killed was a robot Sandra says she knew. She then buries the robot and takes her leave of Bruce.
Sandy eventually went to Samson and revealed that Ricky was his son and missing, and Doc was able to track him to one of Home Base's facilities. After reuniting with him, both Sandy and Ricky seemed to die when Hulk destroyed the facility, but due to her abilities this remains to be seen.
Powers and Abilities
Sandra is effectively immortal,. Her powers allow her to recover from non-lethal injuries. If actually killed, her body is soon restored back to life. The limits to her ability are unknown. She can speed up her recovery time by absorbing the life forces of other beings, through killing them. Blood transfusions using her blood have been able to boost the healing of other humans, though they do not seem to have permanent effects on the recipients.
She is a skilled marksman and has training in unarmed combat. She is not, however, superhuman in these respects.