He was known as the most notorious gang leader, and he was feared by many.

But now. Paulus Shimweefeleni, well known as "Ninja," says he is a changed man as he takes the walk of freedom from the Windhoek Correctional Facility tomorrow, where he had been a resident for 25 years, sentenced for murder.

In a special report, nbc News reporter Selima Henock sat down with Ninja, who shared his journey of crime and transformation. 

Shimweefeleni is a man who was once feared and whose name caused a chill up the spines of those who crossed his paths over two decades ago. 

The 54-year-old's stature could be intimidating, but coming face-to-face with him, Ninja appears meek and gentle.

Shimweefeleni's journey into adulthood began with his being in exile in Angola after escaping the colonial regime in Namibia.

From Angola, he was sent by Swapo to Cuba, where he learned martial arts, which he mastered, earning him the name Ninja.

"When I was in Cuba, I was exposed to many different trainings, and later on, I ended up growing confident that I could defend myself from anyone. I was a difficult person to deal with. I used to beat up offenders. I used to be someone who used power on everybody. I used to be someone who wanted to escape. I escaped in 2005 at Oluno, where I organised myself to be transferred, and I was shot seven times. I am even sitting with two bullets in my legs."

His first experience in prison started when he was in Cuba after fighting with his martial arts teacher. 

His life of crime started when he was introduced to a gang while in the northern parts of the country after returning from Cuba in 1991.

His knowledge of martial arts became his strength and a source of intimidation. A family misunderstanding landed him behind bars, where he was introduced to more gangs.

They would hijack cars, commit robberies, and rob people at gunpoint—a trend he would continue on until one fateful day, when he participated in the torture of a taxi driver, eventually leading to the man's death and Ninja's imprisonment. 

The notorious gang leader was given a life sentence, but after serving 25 years, he was eligible for release under good behaviour.

"The fear that I have is for the deceased's family. I don't know if they are going to find it in their hearts to forgive me; I don't know what they are thinking of me."

It was after a visit by the late President Dr. Hage Geingob at Lucius Sumbwanyambe Mahoto Correctional Services Training College in Omaruru, where he was showcasing his skills with other inmates. 

The Commissioner-General of the Namibia Correctional Service, Raphael Hamunyela, made a comment about his transformation of Saul into Paul.

A popular character in the Bible who was known for persecuting Christians before later transforming into Paul, a transformed man of God,.

Upon returning to his cell, he inquired about the person mentioned by the Commissioner-General and the story behind the names.

That encounter changed his life for good.

"I was encouraged and motivated by that speech and the way our general introduced me to his Excellency; this one used to be Saul and now Paul. On our way to the cell, I went to ask our fellow inmates what he meant by that. They said Saul used to kill pastors; he was a criminal exactly the way you used to be outside. Now that you are here, you are not even running away. He sees you as an example he wants to set. That day I was motivated, and I was still in possession of contraband, so I gave them away."

Over the years behind bars, Shimweefelina has been partaking in different activities, such as tailoring, and he recently completed his certificate in plumbing at Kayeck Vocational Centre.

The correctional facility programmes do not only play a role in rehabilitation but also in recovery.

These are the 'Thinking and Living Skills Programme' and the 'Managing My Substance Programme'. 

Assistant Commissioner Eleanor Nawa, who is the Head of Case Management Services at Windhoek Correctional Facility, explains the programmes. 

"Through the TLS programme that Paulus was talking about, we want offenders to look at their way of thinking because our programmes are based on cognitive behavioural therapy. We want them to look at their way of thinking and how their thinking patterns influence their offending behaviour and lifestyles in general. We want them to make a critical analysis and engage in critical thinking on how their behaviour in the past contributed to the way they committed their offences."

Toivo Simeon was the partner-in-crime of Shimweefeleni. Together, he says, they committed numerous crimes for which he too spent ten years behind bars. Today, he says crime does not pay. He is a changed, career-driven, family man residing in Ongwediva.

Over the years, he has visited Shimweefeleni at the Windhoek Correctional Facility and can attest to his transformation.

Shimweefeleni's plans are to reconcile with those he wronged, to tour schools, and to motivate young people to stay away from crime. 

"I would like to ask for a second chance from our countrymen. I want the government to forgive me. I went to Cuba through the Swapo Party, still with the same people in power. I want to ask for forgiveness from them. They gave me an opportunity to learn something, and when I came back, I missused the chance that I was given. I am asking for forgiveness from everyone, and I need a second chance. After so many years of suffering, I don't think someone can encourage me to go back to where I came from. I will never commit a crime."

He further encourages family members of those incarcerated not to give up on their loved ones and to pay them a visit whenever they can.