Marius Wolfgang the main character OC, is a former army doctor turned engineer who was part of the "Black Dragon" space expedition to assist a colonization effort on a distant planet from Terra. The expedition however was a tragic disaster and Marius was sadly the last survivor as he drifted in space he finally arrived in Zootopia
By Sheer chance he found a most peculiar grey rabbit floating down the river from where he setup his new home in this brave new world he was to inhabit. And after rescuing her from the chilly water he found she was indeed very special when she finally awoke.
Naturally where ever Judy is Nick usually tags along, and this was certainly the case. Marius gave him a bit of a cold reception but after the moment of awkwardness was past they became friendly, and became quite close.
Bogo however was not keen on the idea of his officers being detained by a alien visitor, and after further confrontations became openly hostile to him.