Strange Combine-type aliens taking over Earth, genentically engineering from local genetic material a
#macrofur pop. to act as workers/muscle/enforcers suited to this environment, local sapients too small/weak for many of their needs. Then turmoil elsewhere in the empire, macrofurs rebel Earth is freed, but no longer is it host to a single sapient species. The macrofurs rightfully also claim it as their home planet. Them being bigger, the alien tech locked to their genentics, their brains being the only ones that understand/wield/reproduce that tech, it seems only natural to them that humans would fall into a secondary, little sibling, sidekick like role ๐คญ Helpful, 'tiny assistants' to their 'BIG heroes' in their mission to push back the menace that took over their shared planet.