Paul and JP Norden are brothers and best friends, and for many, they represent the defiance and resilience Boston showed after the bombings at the famed Boston marathon last year.

The Norden brothers each lost a leg in the double explosions on April 15, but they believe their lives are better now.

"Even though this was such a bad tragedy and stuff, I feel like we're more positive people now than we were a year ago," JP Norden said in an interview with ABC News' Amy Robach.

'I'm Happy'

His brother added: "I'm just very happy now … Like, before I would have said I was - maybe, like, just content. But now I'm, like, happy."

The brothers, who worked together as roofers, were nearly killed in the attacks allegedly carried out by another pair of brothers, Dzhokhar Tsarnaev and Tamerlan Tsarnaev. The twin explosions near the finish line of the marathon killed three people and injured 260 others.

Dzhokhar Tsarnaev is currently awaiting trial. He has pleaded not guilty to 30 counts relating to the bombings. His brother was killed in a shootout with police three days after the bombing.

Haunting Photos From the Boston Marathon Bombing

The injured Nordens were rushed to two different hospitals, where they wondered if the other brother had survived. Paul Norden, 32, was in a coma for nearly a week.

Two weeks after the attack, the brothers had an emotional reunion.

Those days they were apart were tough, JP Norden, 34, said.

"You wonder, like, what we're going to do, what- how things are going to be the rest of our life," he said. "You know, what's it going to be like with your girlfriend? How's life going to be?"

They slowly rebuilt their lives. After more than 50 surgeries between them, and months in the hospital, they got a huge dose of hope in the summer when they were each fitted with a new prosthetic leg.

Paul Norden recalled the emotional moment that he first stood up on the new leg. He called it "amazing."

"You wanted to cry. It was, like, so overwhelming … (it) was, if not the best feeling', definitely one of the best feelings of my entire life," he said.

New Leg Felt Good

His brother remembers feeling like himself again.

"Like, I didn't even take a step … when I stood up, I was, like, 'Wow, this - this feels good," JP Norden said.

Walking alongside Robach, the brothers said they had hope that life could be close to what it was before. When they were in the hospital, they wouldn't have believed they could experience such a turnaround, they said.

The Norden brothers have written a book about their experiences. In " Twice as Strong: 12 Seconds, 2 Brothers and the Marathon that Changed Their Lives," they recount the blasts and their journey to overcome their injuries.

Their progress has lifted the spirits of Liz Norden, the men's mother.

"Just seeing them walk and getting back to, you know, being their new normal, it's just amazing … I mean, it really is - a proud moment," she said.

Paul Norden can shoot hoops, and his brother hasn't gone running just yet, but knows he'll do just fine when he does.

Love Made Stronger

JP Norden and his girlfriend, 25-year-old Kelly Castine, are stronger than ever. And Paul Norden and his girlfriend, 26-year-old Jacqui Webb, are now engaged.

"At the worst of the worst, they didn't care, it didn't matter," JP Norden said.

"They stuck with us," his brother added.

While the Norden brothers may have adjusted to their new lives, their mother won't calmly accept what was done to her sons.

"I'm angry. They're not," said the 51-year-old mother of five. "They've accepted it. And, you know … moved on. But I'm a little angry."

Asked whether she wants justice, she replied: "I do," and when Robach asked her what she considered justice, she said: "Well, I really want to see the death penalty."

Unlike his mother, Paul Norden isn't angry.

"Like, obviously, I wish it didn't happen. But … things happen in life that you can't control. So you just push forward, move - work hard. And I think positive things will happen," he said.

Added his brother: "I believe whatever they do to (the suspect), whatever happens, I think that will be just … We think about, like, moving forward, getting stronger and where our lives are going, not where his is going."

The brothers also have a message for others.

"Always have hope because there's a good shot you - everything will be all right … Like, if you just keep fighting and working hard, I really think, like, you will be fine," Paul Norden said, smiling.

JP Norden wants others to seize the day.

"You know, live life how you can or how you want, not - don't wait to say, 'OK, I just lost my leg. Now I'm going start doing all this stuff.' Do it now," he said.