LEE'S SUMMIT, Mo. -- To students at one metro high school, he was a superhero.
"Superman Sam" Smith, 19, passed away on Easter Sunday morning, having fought cancer for most of his young adult life. Smith's family members and friends say they've lost a tough fighter and a wonderful person.
The end of a five-year battle against cancer has ended. Everyone around Lee's Summit West High School knew Smith, and his fight for good health.
"Superman Sam," as he was affectionately known, ended his battle with cancer around 4.a.m. on Sunday, passing away peacefully with loved ones and schoolmates by his side.
"I've lost this person in my life who brought me a great deal of happiness," Liz Haus, Smith's girlfriend, told FOX 4 News on Monday.
Haus says she and Smith had dated for over two years, having met as teammates on the Titans swim team. She watched as Sam went into remission in 2015, but then, his cancer returned, and his family sought help from oncologists at M.D. Anderson Cancer Center in Texas, as the cancer spread from his leg into his lungs and throat.
"It's very hard to hear because I know how hard he fought, and that he wasn't able. He lost. It's sad," Haus said. "He's probably the hardest fighter I've ever met in my life."
FOX 4 News had followed Sam's progression over a four-year period, both through times of good health and bad, as he fought pediatric cancer. Smith kept his fight up throughout high school, and had recently graduated from Lee's Summit West High School, and had intentions of attending college, before his health took a turn for the worse.
"He constantly got bad news. He never gave up. He always stayed positive," Haus said.
Smith's cancer was first diagnosed five years ago, after breaking his leg during a football practice. Doctors discovered cancerous lesions in his leg during an examination. Bennett Fredrickson, Sam's best friend, was in uniform during that practice. He says he visited Smith's family before sunrise on Sunday, as Sam finished the fight.
"I grew up with him. I played football with him," Fredrickson said. "Sam taught me how to be a man. I really looked up to Sam, and the way he acted. What he did for his family. How he presented himself. I thought that was really cool."
"He's the greatest person that I've ever met. Just, he's great," Haus said.
This isn't the only tragedy the Smiths have suffered in recent years. Last August, Tony Smith, Sam's father, died of a heart attack while waterskiing. Now, his family says they're happy the two are reunited in heaven.
Smith's brother, Henry, tells FOX 4 News Sam's funeral services will be held this weekend at Colonial Presbyterian Church in South Kansas City.
"He fought cancer for so long, and fought to his last breath," Henry Smith said. "He showed strength around everyone else to keep his pain from affecting others."
Colleen Gibler, who's spent 12 years as Lee's Summit West swim coach, says Smith was an inspiration to others, and she believes it's somehow appropriate that he passed away on Easter Sunday.
"His peers have grown up in a different way. They've all become adults far too early in dealing with his tragedy, but they've become wonderful young adults with a strong faith and a different perspective on what it means to fight through things," Gibler said.
Gibler says her remaining Titan swimmers are planning to build a memorial garden at the Smith family home -- a gesture, and a token of appreciation, and a certainty that Smith's legacy will continue to grow.
"They won't realize the effect he's had on them for years to come. When it hits them, they're going to realize Sam was really something."