The killer was made to serve mother nature
Mother nature may be angry with how humans, especially wild teenagers, have disrespected her lands and creatures. So she's using the killer to hunt them down as revenge. This is made more apparent given the word nature in the title and how the killer first appeared coming out of the Earth. Connected to the killer
One of the visiting teenagers, or locals who appear in the movie, will have a familiar connection to the killer as a way to humanize them.