Moraga, who grew up on the wrong side of Phoenix, is stepping into the cage at KeyArena on the televised card to ensure his two sons have the happy childhood he didn't have.
Champion Demetrious (Mighty Mouse) Johnson, who became a father for the first time last Friday, stands in his way.
The 29-year-old Moraga is unfamiliar to many MMA fans. The 125-pound flyweight division is the UFC's newest on the men's side and Moraga has fought just twice in the organization, both on undercards.
But his story is beginning to trickle out.
"I came from nothing," said Moraga, who talks of buying furniture for his family when asked what he had done with his fight earnings.
Moraga (13-1) has endured more than his share of pain. His best friend was stabbed to death in 2003, a tragedy that stayed with him.
Wrestling — he was an all-American at Arizona State — then MMA helped give him a focus. But there was more pain.
His cousin Jesse (Jay) Rocha was shot to death in February. Moraga was helping bury him the day he got the call offering him the UFC title shot.
The championship fight is fraught with memories. Saturday marks the 10th anniversary of his friend's death. Moraga says he reflects on the journey that brought him here "all the time."
"It just reinforces to me that this is what I was meant to do. This is destiny. I've gone through so much. I just feel it had to be for a reason."
It is perhaps no wonder that Moraga, who normally walks around at 140 pounds, is five foot six of burning desire.
"I feel I can be beat, but I can beat anybody," he said pithily.
Some oddsmakers have made Johnson a 5-1 favourite. Moraga, fighting in the champion's backyard, says it will just be that much sweeter when he wins.
"I like going against the odds. I like proving people wrong," he said. "I like taking the hardest challenge. Don't give me the easy route, because then there's going to be doubt later."
The spotlight is new to Moraga. While not unwilling to fulfil his media responsibilities, he doesn't exactly like opening up.
"It's just nobody's business really," he said, when asked why. "I just like to be a private person, just keep to myself. But it doesn't work like that."
A lot more people might get to know him after this weekend, Moraga is reminded.
"They definitely will. I promise you that," he said.
"There's a lot more to my story," he added. "After I win the (championship) belt, you guys will get to know more."
Moraga is not fighting for fame or glory.
"Just pay me and I'm happy," he said with a laugh.
"I just want to give my kids what I didn't have. Make my life a little bit more comfortable. I've suffered for so long. So it's my time to get something now in return."
Moraga, who made his pro debut in November 2009, said he got serious about fighting when his girlfriend, his high school sweetheart, got pregnant.
He looked around at more successful fighters to see what was missing. His conclusion was that "outside distractions" had robbed him of focus.
"Even though at the time I thought I was giving it my all, I really didn't give it my all. So I went all in for MMA. No games. I saw the sacrifices I didn't make before and I made those sacrifices this time around. And it will pay off."
The turning point was when he went to Dominick Cruz's camp to help the bantamweight champion prepare for his October 2011 title defence against Johnson.
"I just saw the extra push, how he went the extra mile or miles," Moraga recalled. "Dom's a beast. That definitely opened my eyes right there and I think after that, I really tightened up everything and got on it."
These days he trains alongside UFC lightweight champion Benson Henderson, another fighter known for his work ethic.
Moraga has a knockout and submission win to date in the UFC, finishing Chris Cariaso last time out via guillotine choke.
Moraga may have his hands full running down the five-foot-three Johnson, a ball of energy who is constantly on the move. Johnson (17-2-1) is 5-1-1 in the UFC against elite opposition. But some wonder what might happen if the hard-nosed Moraga catches him.
Moraga has won seven straight while Johnson is unbeaten in four.
Fatherhood is also on Johnson's mind these days. He and wife Destiny had their first child, a boy named Tyren, last Friday.
Johnson, 26, has also worked hard to get where he is. He used to combine training with a full-time job at a recycling plant in nearby Tacoma. He called himself a "utility man,'' doing everything from operating machinery and forklifts to packaging material.
He used to work from 7 a.m. to 3 p.m., then train from 3 to 7. These days fighting pays the bills.
Johnson's right forearm is covering with inspirational words in permanent ink. The tattoo dates back to his amateur fighting days when he suffered a string of injuries. He says he had it done to remind him why he got into MMA and why he continues to make the sacrifice.
While small in stature, Johnson has a larger-than-life personality.
But Moraga says Johnson is boring in the cage, accusing him of not trying to finish fights.
"That's just me, man ... You ask me a question, I'm going to answer you," he said later.
Moraga says unlike Johnson, he takes the risk to try and finish his opponent.
"He, for the most part, plays it safe, he uses footwork. He's cool with running around for the whole fight if you're going to be chasing him."
Moraga doesn't plan to play that game. "The ball's in our court this fight."
Asked to list fighters he likes to watch, Moraga lists off the likes of Donald (Cowboy) Cerrone, brothers Nate and Nick Diaz, and heavyweight champion Cain Velasquez, a former college teammate.
"I like people that go in there, that get after it," he said. "They're not afraid to get hit, they're going for the kill. They're making the fight exciting. I think all fights fans truly like that."
While fans appreciate the skills of champions like Johnson and welterweight title-holder Georges St-Pierre, Moraga says the excitement can be lacking if they play it safe.
"I don't want to be known as that fighter," said Moraga.
Counters Johnson: "The last time I checked, the name of game is it, not to be hit."
"Each time I get into the Octagon, I just start painting," he explained. "I just black out, I just start painting. That's my craft."