Denal was a clone trooper commander in the elite 501st Legion. Considered one of the most experienced members of that unit, he survived many Clone Wars campaigns alongside Captain Rex and Jedi General Anakin Skywalker. At the start of the war, Denal accompanied Rex, Skywalker, and Tano on a mission to destroy the Skytop Station, a Separatist listening post located on one of the three moons of the planet Ruusan. The group successfully completed their mission, blowing up the station with several explosive charges. Of the five-man squad of clones that was sent there along with the Jedi, only Denal and Rex survived the mission.
Denal also saw action on Rodia, Tatooine and Orto Plutonia, conducting many missions on those planets. He rescued a battalion of clone troopers from a Separatist ambush, recovered a lost Republic cargo, and helped a Jedi in distress defeat a force of battle droids. On one occasion, he even saved General Skywalker's Padawan Ahsoka Tano from a Separatist prison on Tatooine. Denal was also involved in the discovery and destruction of a new Confederacy superweapon—one that could prevent Republic radar from detecting enemy armies. (I got this from Wookiepidia)