MoonCat

MoonCat is the het ship between Marc Spector and Greer Nelson from the Marvel fandom.

Canon
Marc and Greer became romantically entangled soon after the former was recruited into the Avengers, maintaining a brief on-again off-again relationship. After being ordered and sent by the team to spy and check on Marc after his recent split with the Egyptian God Khonshu due to being manipulated and taken advantage of into aiding him in an attempted global conquest, Greer would have frequent check-ups on Marc. Greer sensed the repressed negative emotions Marc was struggling with after the damage Khonshu had done to him, which had resulted in Marc's estrangement from his wife who left the country with their daughter out of fear of what he had become.

Marc would open up to her about his emotional struggle, to which she would comfort him on whilst she dealt with the inner conflict of having to spy on one of her closest friends, voicing her frustration of this to King T'Challa, who insisted she continue her assignment. Joining Marc on one of his missions, she would help him in his hunt for the villain known as Zodiac, and eventually tells him of her mission out of guilt, but is surprisingly told by Marc that he already knew of this and just wanted a friend, understanding why Black Panther would want him under surveillance and wanting Tigra to keep him grounded regardless.

Greer would accompany Marc as his date to a gathering of vampires, the two then jokingly huddling under an umbrella as they douse the party with water from the rooms sprinkler system, with Marc then consecrating the water in Khonshus name converting it into holy water, killing most of the vampires with the two teaming up against the remaining survivors. After Midnight Man, one of Marc's deceased enemies seemingly returns from the dead, Greer launches her own investigation on the matter, driven by her animalistic instinct to hunt. Marc is suspiciously unfazed by the apparent return of one of his villains, and Greer quickly uncovers the truth behind these strange events. At night, she ambushes and pounces on an unexpecting Midnight Man on a rooftop, pinning him to the ground and clawing his mask, revealing to be Marc all along, masquerading as one of his villains to rip off criminals to pay for all his debts after his funds were stolen away. Greer is heartbroken by his dishonesty to her even after she left the Avengers for him, and she leaves in tears. Marc visits her later that night, apologising for once again hurting another person he loves, and Greer kisses him, mending their friendship and the two now dating.

Fanon
The ship between Greer and Marc quickly became one of Marc's most popular comic romances, especially after it recently reignited in the modern comic era. It grew reasonably after the 22nd Issue in the Moon Knight comic series, being entirely from the perspective of Greer, and also being the one where she and Marc get back together. Most fans found the relationship between them compelling even when it had been depicted as platonic in earlier issues, with Greer being a character Marc can easily bounce off of as both are comedically just as dysfunctional as the other.

Fandom
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