Irvin Senate is an ex-mercenary and the former captain of the Dark Athena.
Senate had always seen himself as a good businessman, a decent mercenary with an excellent eye for profitable schemes.
Captain of the Athena
Sometime during the Wailing Wars, Senate acquired and armed the Bellocka MV, renaming it the Locust. As Captain of the ship, Senate was a respected man with a loyal crew - until he arrived on Sol Lucia and took Gale Revas aboard as a prisoner of war, then 18 years old. Revas quickly took to the mercenary lifestyle and, unbeknownst to him, began to earn the loyalty of his men.
Eventually, Senate devised a plan to use bio-mechanical drone technology he had acquired to turn death-row prisoners into remote control cannon fodder and sell them to the highest bidder, but Revas decided to go a step further - she wanted to take entire planets and make them into drone armies to sell. When a disgusted Senate refused, Revas repeatedly poisoned his food and drink until he was nearly insane from its effects, and then incited a coup to take control of his ship for herself.
Sometime after his imprisonment, Senate was (optionally) approached by Richard B. Riddick, who was seeking information about the Dark Athena in order to escape, and told him about his fall as captain. After Riddick released all of the prisoners from their cells, Senate, as well as his former second in command, Yoto, and most of the others were gunned down by the Dark Athena's mechs.