agent with a unique amount of experience dealing with alternate realities, time travel and alien beings. She even fought a zombie
once. Her special qualifications got her tasked by
situation. The belief was that Mar-Vell had come forward in time and needed to be monitored to ensure he didn't die in the present, which would alter the past.
Agent Sante found and made contacted with Mar-Vell at the Louvre, where he was obsessing over a painting. She seemed to amuse him, and after their brief talk, he returned to the United States and made his presence known to the public. He also submitted to Stark's wishes and secluded himself in an apartment at Avengers Tower
. Sante was brought back to the U.S. as well and informed that she was still on Mar-Vell detail. However, she wouldn't be making face-to-face contact with him as she desired. Stark instead wanted her to focus on investigating the strange connection he has to the painting from the Louvre.
Her investigation didn't give her any answers beyond exposing how deep Mar-Vell's obsession with the painting ran. Talking with Stark, it was decided that she should start investigating the world around Mar-Vell, starting with the Church of Hala
that he recently been founded. She went undercover and joined the church's membership. While skulking around, she overheard some of the legit members being panicked and talking about a member who had died in a fall. She snuck past to see for herself and found the dead member of the church laid out on a table. In death, the man had reverted into a Skrull
This discovery took Agent Sante's investigation in a new direction. She found records on the Skrull corpse that revealed it had been the Skrulls behind the series of attacks on Mar-Vell. Using this new information, she located a hidden Skrull facility and spent three days going through all the information she found available. This was how she learned the truth about Mar-Vell. He was not Mar-Vell. He was Khn'nr
, a Skrull volunteer who had been genetically and psychologically modified to be a perfect impersonation of Mar-Vell. The process turning into this had gone wrong, and he escaped. While she was there, Mar-Vell -- no, Khn'nr -- returned via a Negative Zone
portal. His return to this place trigger the memories of his escape and what he truly was. She confronted him, calling him a liar and a malfunctioning weapon.
Khn'nr convinced her that he was choosing to be the hero Mar-Vell over an invading Skrull. He told her he could have killed her already if he wanted and that if she truly did not believe him then she should shoot him. She chose to believe him.
Secret InvasionFor further details: Secret Invasion
As the only one to know the truth and that Khn'nr was still around, Agent Sante assisted him in trying to find a way to stop the impending Skrull invasion. She used her contacts in S.H.I.E.L.D. to decrypt Skrull intelligence they recovered from the hidden facility, but they found it to be useless. It showed things like how the fleet were to be positioned over Earth but not how the Skrulls intended to get that far or any of their actual strategy. She told Khn'nr that they needed help with this, despite not knowing who they could trust.
She later returned to find Khn'nr gone and a letter left for her. In it, Khn'nr apologized for leaving and doing what he felt he had to do. He was no longer sure he could stop the Skrull invasion, so he had left to do what little good he could do while the invasion happened. She didn't see him again as he died in the process.
It is unknown what happened to Agent Sante after S.H.I.E.L.D. was dismantled and whether she became an agent of H.A.M.M.E.R.
as many others did.