Based on the Nordic urban legend of the Tag Vandren. These androgynous Scandinavian beings average at seven feet tall and have large humanoid bodies with other mammalian features depending on their habitat (for example; coastal subspecies look like seals/otters while the arctic variety look like lynxes) the most common variation being domestic cats.
They stay close to human settlements and are fond of using houses and trees like jungle gyms, with the development of skyscrapers and apartment blocks they find that the best climbing spots are in the city. The only problem with this is that they make awful banging and scrapping noises while climbing that are often mistaken for cooling pipes or rats in the walls.
They also make a habit of running beside cars, keeping up with the speed by using roadside obstacles to propel themselves forward. Many young children see their first Roof Walker while on long road trips, with the creatures being practically invisible to those in the front seats.
They dress in grubby stolen clothing, often dressing very warmly for disguise and to protect them from cold wind. Easily mistaken for a person at night (their prime hunting time) and pose little threat to humans unless they're very old or ill, meaning that they won't object to luring in a drunken human before tearing off a limb or two.
Notoriously impish, they enjoy playing pranks and games, especially with human children. Despite their mischief they can be near monstrous when a child is harmed.
The most well known Roof Walker sighting was where a well known sex offender attempted to kidnap a three year old boy, only for a passerby to tear the offenders arms off and retreat up a tree with the boy safely wrapped in it's cloaked form.
It was only the next morning did the neighbourhood find the boy completely covered with ragged coats and blankets, still up the tree and demanding to know where the "kitty cat" had gone.