Damren was a Reptilian of the multi-species race Xindi. He was a colleague of Degra and helped him on the planet-destroying weapon project. However, Damren, like many Reptilians, thought that a bioweapon or toxin would be more effective against the Earth's population. After the Xindi Council rejected his proposal, Damren and two of his researchers disappeared.
Damren and his team, in actuality, traveled back in time to Detroit, Michigan in the year 2004, with help from the Sphere-Builders. For two months, they began synnthesizing a bioweapon based on human blood types. They employed a human named Loomis to bring one from each blood type, paying him $5,000 for each one.
The Reptilians nearly succeeded in completing the bioweapon. Unfortunately, Jonathan Archer and T'Pol, from the Earth ship Enterprise NX-01, traveled back in time to stop their plan with help from Daniels, who informed them of their actions. Archer and T'Pol killed Damren's colleagues and Damren prepared to release the portion of the virus that they had completed when Archer cornered and mortally wounded him. Damren used his last ounce of strength to roll the container that held the virus into a ventilation fan, but Archer was able to catch it before it would kill a large portion of Earth's population. The body of Damren, his team, and all their equipment were then taken back to Enterprise in 2153.
In January of 2154, Degra and Janar boarded Enterprise and agreed not to launch their weapon if Archer could provide proof that they were manipulated to attack Earth. Archer showed them Damren and his team and their technology to show that the Reptilians did secretly build a bioweapon.