History
Cynthia was found trapped in Ant Hill by the X-Men.[2]
She was fascinated by the Sentinels and dedicated to learning more about them she funded an expedition and digging into Ant Hill to uncover the underground complex that had the defunct Sentinels that the Avengers had defeated in the past, although once she and the team that did the dig arrived underground she was betrayed by the rest since they wanted to sell the remains of the Sentinels for profit but then one of the Sentinels reactivated itself killing everyone but Cynthia that was left trapped.
After being freed by the X-Men she accompanied them to fight the Sentinels, after the X-Men defeated them and left her in there she revealed that she planned to build new ones so that they could eradicate mutantkind permanently and make her be remembered forever in history, to accomplish that goal she teamed up with Abomination.[3]
In reality her true reasoning for building a new Sentinel was to extend her life, but before her mind was fully transferred into the newly built Sentinel that she made, the Sentinel reinstituted his previous programming killing her body in the process, then with her mind inside of the Sentinel she took control of the body and threw herself into the Sun before the Sentinel part of her took over and did any more harm to anyone.[1]