Moorwen is the name given to an alien monster from the sci-fi film Outlander.
It was transported to Viking-era Norway due to it smuggling itself into a spacecraft being used by Kainan, a survivor from a distant world that was ravaged by the Moorwen: the rest of the film deals with Kainan's struggle to stop the Moorwen from killing the largely hapless Norse people while also trying to adapt to the alien world of medieval Earth. The Moorwen served as the main antagonist of Outlander.
In a flashback, it is shown that the planet that belonged to the Moorwen and the rest of its species was taken by Kainan and his people, in which they mercilessly slaughtered most of the Moorwens and selfishly took their homeworld. Only one Moorwen survived and, full of fury and vengeance towards Kainan and his people for killing the rest of its kind and taking their home, attacked its invaders' compound while the military were away, killing all of the defenseless civilians in the compound, including Kainan's wife and son.
Due to the tragic backstory of the Moorwens, the alien monster can be considered as not really a villain, just an innocent yet carnivorous creature that has lost everything for no good reason and wanted revenge on those who had cold-heartedly taken everything from it, and that Kainan's people were the true baddies, even though Kainan does feel great remorse for having to be involved in the Moorwen genocide and is trying to atone for his sins. In the final battle between the last surviving Moorwen and Kainan, the latter is forced to cut off the former's arm while dangling from a waterfall cliff, sending the alien creature plummetting to the surface below and ultimately killing it, and making the Moorwen species permanently extinct.