Rasonian Marines or the Rasonia’s Naval Infantry.
Their purpose? None, really, just a better infantry than their basic ground forces.

I don’t even know if they’ll even make an appearance in the series, since they’re chilling in the ocean much.

A city map, thoughts?

THE HUNCHBACK
What the dog doin?

The hunchback is a victim of any type of back spinal syndromes, infected during the outbreak and unable to do things like climbing or running properly, the virus mutated them into a four legged monster, now capable of outrunning survivors and leaping further than any average infecteds, the variant becomes a terrifying enemy.

The Hunchback attacks by leaping onto their victims and starts beating their head to a pulp, with enough punches to the head, it begins feasting, eating through the broken skull fragments it has previously smashed apart.

This threat is slightly significant for the RSU, it is simply an obstacle for combative units, it can easily be dealt with just a few shot in the head, only thing worrying about this thing is its speedy capabilities.