Seesay
Seesay was a human member of the Australian Secret Service.
Together with another agent, Browning, he was tasked with protecting O at his house in the Australian Outback. He remarked it was worth making the journey when the TARDIS arrived at the house along with the Thirteenth Doctor and Graham.
Later that evening he and Browning investigated the perimeter of the site when some movement sensors were triggered. When the Doctor, Graham and O came outside Sessay ordered them back in telling them to figure out the bigger problem. Seesay then went round the back of the house telling Blackwood to stay in communication.
Seeing more movement sensors being triggered Seesay rejoined his colleague only for them to be confronted by a crowd of Kasaavin who them, apparently, attacked and killed them. (TV: Spyfall)