Shifters are driven by three simple instincts; consume, change, breed. Shifters "feed" on the memories and genetic information of other creatures; killing them and absorbing their genes through their leathery tendrils. With this, they acquire both their genetic memory and visage.
While in human form, shifters are indiscernible. The only way to reveal a shifter is their eyes; their irises reflect light by reflexively blinking a vertical set of eyelid membranes similar to reptiles. This trait is also seen on camera, as all shifters appear with glowing eyes.
By virtue of their versatile genetic and molecular structures, shifters are highly resilient; capable of regrowing limbs, provided they have enough biological material to consume to fuel their healing process. They cannot, however, survive beheading or being completely immolated.
Shifters may also augment their strength and durability - at the expense of their speed and agility - by channeling biomass into their muscles to harden their skin and enhance their musclemass; doubling their already-inhuman strength and enabling them to bash aside road vehicles.