Lord Gaben

Lord Gaben is the overseer of the Valve Corporation and the boss of The G-Man. He is the overarching antagonist of the Half-Life series.

History
In 1998, Lord Gaben sent The G-Man to observe Gordon Freeman's actions at the Black Mesa Research Facility and later employ him.

Following the events of Half-Life 2: Episode Two, Gaben rendered G-Man temporarily unemployed as he pondered along with the rest of the employers on how to take their actions further. It took 12 years for Gaben to get the G-Man back on board, by which point G-Man was living under the alias of Mr Blackstone to make ends meet on earth. G-Man accepted an offer to work for Gaben again and used time travel to create a cosmic retcon, which resulted in Eli Vance being spared of death and Alyx Vance replacing Gordon Freeman as the new field agent.

Gaben once again went quiet, and G-man returned to a mundane life and accepted he would have to wait another 12 years for a new assignment.