Thomas Whitman is one of the members of Roland Deschain's original ka-tet and he trained with Roland under Cort as apprentice gunslinger's.
He was the only male heir of the Hattlen family name and so became a gunslinger because of this, despite his mother never wanting this to happen. It was when his training began he quickly became friends with Jamie De Curry and Roland Deschain which his family favoured hoping he would one day become one of Roland's chief councillors when he became Dinh of Gilead.
He is killed at the battle of Jericho Hill alongside many others by a flame-thrower. He felt strongly that Gilead should be cleansed of all Slow Mutants that had infested the city after it fell even though they didn't have enough men to do so.