See tsunami anniversary photo gallery (http://www.irinnews.org/multimedia/tsunami/index.html)
Five years on he remembers how Indonesia's worst natural disaster pushed both sides of the conflict together. Khalidan is now the elected head of Lamee village and one of thousands of former separatist fighters working in the government. He told IRIN about that day:
"I joined GAM in 1996. Life during the conflict was hard for us. We often went without food, and fought hungry.
"We fought as guerrillas. We never had a permanent base. We were always on the move so that the enemy could not detect us. If the enemy [the Indonesian military, TNI] detected us, we would immediately move, whether it was day or night.
"After martial law was declared [in May 2003], we had frequent skirmishes with the TNI.
"On the day of the tsunami, we were in a small camp about 11km inland and felt an earthquake around 8am. It wasn't until later that we learned by radio from friends who lived near the ocean that there had been a tsunami.
"We crept quietly down to the coast to check out the situation. When we saw what had happened, we helped to remove bodies. There were so many bodies. The TNI were also helping, but they did not know that we were GAM members, since we weren't wearing any uniforms or markings. We were there to help people, so we didn't have our weapons with us.
"We didn't have any food, so we took some of the aid from NGO workers.
"[When the peace agreement was signed in August 2005] we had no idea such an arrangement would be possible. Those at higher levels of GAM might have known it was coming, but at the lower level, there was no warning. The tsunami changed everything.
"When I have nothing else to do, I often think about the bitterness of living in the woods. There are no sweet memories. We were starving and we had to eat leaves, while today we can live at home with our wives and family.
"Now my duty as head of the village is to serve the people. I delegate administrative tasks to the secretary, and give authority to other officials elected by the people. We receive our budget from the sub-district. If we didn't deliver all of it to the people, and took some for ourselves, people would vote us out.
"The most important thing is justice. When we had disputes - between GAM and the Indonesian government - we were only looking for justice. Since there was no justice, there was conflict.
"My greatest wish is for conditions in Aceh to continue improving. If all the articles of the [peace agreement] are implemented, I don't think there will be a new separatist movement. But if not, it's possible that our descendants will take up arms again."