Simon Peter Lotia is not only more than twice the age and double the height of his fellow pupils at Rengen primary school in northeast Uganda, but he towers over most of his teachers as well.
For many of the years when he should have been in school, Lotia, 23, was launching bloody cattle raids against other clans across Uganda's remostest and most volatile region, Karamoja.
Now, Lotia has swapped his automatic weapon for an arithmetic book and joined a growing number of former warriors who have decided that it is finally time to start going to school.
"I had a very difficult time when most of my friends died in cattle raids and then all our cows were taken by people from another village," told AFP, during a recent reporting trip supported by the Pulitzer Center.
"It was then that I decided that I had to leave that life and start going to school," Lotia said.
The most underdeveloped region in Uganda, Karamoja has for generations been plagued by a cycle of neglect and tit-for-tat cattle-raiding between clans.
Now, after over a decade of often brutal disarmament campaigns by the Ugandan army, the government says that the number of guns has gone down significantly and that cattle-raiding is dying out.
"Since the forceful disarmament process we have seen a real rise in the number of these former warriors coming to school," said Helen Sunday, the Rengen primary school headmistress.
Encouraged by the promise of free primary education and by improved security conditions, the former warriors are able to start their long delayed education - but there are some teething problems.
"When you come to school you have school rules, which govern the school activities," Sunday said.
"You find also that the young kids can bully these big ones, telling them they are too big and are fit to be fathers."
Beyond the initial problems, however, local charities working with the former cattle raiders say that although the number of them signing up for school has risen, many of them struggle to cover the cost of books, accommodation and uniforms and end up dropping out.
And while a few lucky ones may make it through, most former warriors feel they have been let down by the authorities and that prospects for finding a job in Karamoja - even for those who do finish school - are almost non-existent.
"Tomorrow these warriors could acquire guns and then become very dangerous again if the government doesn’t help create more opportunities," said Sylvesto Konyen, a human rights officer for local charity Kopein.
"Something needs to be done to help them now that they have been made to give up their old way of life," Konyen said.
Back in the classroom Lotia said that having seen many friends killed in cattle raids he understands how fortunate he is. After coming in the top ten in his class last term, he is focusing on improving his grades and aiming to complete another eight years of school before hopefully going on to study further.
"I want to study and maybe become a doctor or a teacher," he said. "I don’t want to go back to my life as a warrior, I want to stay here and finish school."