A Marine wounded in combat in Fallujah, Iraq, in 2004 has found new purpose as a self-proclaimed peaceful warrior fighting against a 1,172-mile pipeline that protesters fear threatens the water source of Native Americans in North Dakota.

Catcher Cuts The Rope, a member of the Lakota tribe, told filmmaker Keely Kernan that his recovery from serious shrapnel injuries led him to the kind of action where indigenous tribes have joined to support the Standing Rock Sioux’s opposition to the Dakota Access Pipeline.

“I saw a lot of death and destruction,” he said about his military service. “I was profoundly changed and affected by that.”

For months, the Standing Rock Sioux and allies have opposed the $3.8 billion pipeline, because they fear it could leak into their drinking water when it runs beneath Lake Oahe, and they claim it violates the terms of an 1851 treaty with the tribe.

“When I heard that our relatives here, our Lakota brothers and sisters, were gong to stand up to these oil companies, to this black snake with prayer, it woke up something inside me that was good, that had a lot of hope,” Cuts The Rope said.

Hundreds of veterans have pledged to self-deploy to North Dakota on Dec. 4 to support the Standing Rock Sioux and others aligned against the interstate pipeline.

But recent orders make it uncertain whether the vets will reach their destination. North Dakota Gov. Jack Dalrymple (R) ordered protesters to immediately evacuate the camp because of a winter storm, and the Army Corps of Engineers declared that the Oceti Sakowin camp will be closed to the public on Dec. 5. Law enforcement has also vowed to turn back vehicles carrying supplies to the stranded campers.

Many of the protesters prefer to call themselves “water protectors” as they try guarding the Missouri River and its offshoots from oil leaks. But Cuts The Rope said it is as much a spiritual problem as a literal chemical crisis to avert.

“We can’t let the few that have hate and and fear and greed in their hearts ruin it for everybody,” he said in the film above. “The water is not only being polluted by oil and pollution. It’s being polluted by hate. It’s being polluted by fear.”