Yeah, now that I remember the episode in question it definitely was an attempt at some sort of spin off show. I don't think anything ever happened with it but it would have been interesting to see how it played out.
apparently the character has been used in some AVENGERS (British show) Novels and some other writings to include some ST stuff. non canon, but still shows the impression one character from one ep of TOS made on ppl to be used so much.
for example in the eugenics wars; gary 7 is id'd as the person responsible for placing Khan on the BOTANY BAY
(Yeah, I looked him up )
from his 'wiki'
Star Trek novels[edit]
In
Greg Cox's
The Eugenics Wars novels, Gary Seven had numerous dealings with
Khan Noonien Singh and initially hopes to train Khan as his successor. Along with his now-partner Roberta Lincoln, Seven tries to prevent
World War III in a variety of ways. Seven leaves Earth in 1996, after sending Khan on the DY-100 class
sleeper ship SS
Botany Bay.
Cox also wrote a 1997 novel,
Assignment: Eternity, featuring Seven. In this novel, the alien agency which Seven works for is called the "Aegis", though whether this refers to the organization or the alien species in charge of the organization is unclear.
Seven is mentioned, but not seen, in the
Star Trek: Department of Temporal Investigations: Watching the Clock novels as well as the 2017 novel
Star Trek: The Next Generation: Hearts and Minds .
