Captain Hansen Haile is a soldier of Westmarch.
Haile served Westmarch and won great fame for himself. He "won hundreds of lost causes" all over Sanctuary. Supposedly, King Justinian IV had to threaten him with treason just to get him to return home to accept a promotion.
The Siege of Bastion's Keep
""More of the brutes from below, Captain! What do we do?"
"Private, if you need to be told which end of the sword goes where, you haven’t been paying attention! Fight to your last breath, lads!"
— Hansen rallies his men(src)
In 1285, Haile, now a captain, was stationed at Bastion's Keep when it was besieged by Azmodan. He led his men at the Stonefort. During the siege, a Siegebreaker Assault Beast was unleashed upon the fortress, though Haile and 100 soldiers were able to bring it down. On tne ninth day of the siege, Commander Calderos planned to lead a charge out of the keep on the following day, intending to scatter the demons. Haile commented that Calderos could "commit suicide by stupidity" if he wanted to, but he'd be damned if he sent any of his men with him.
By the time The Nephalem arrived, Haile was down to just four soldiers. With The Nephalem's aid, his men was able to raise one of the catapults, holding the demons at bay. Haile told The Nephalem that it was an honor to fight at their side.
Haile encountered The Nephalem again later in the battle at Rakkis Crossing; all of his men had perished during the charge against Azmodan's lair. The Nephalem aided him in fighting off a group of demons.
Azmodan was defeated, but Adria betrayed her allies, killing numerous people in the keep, and allowing Diablo to be reborn. Haile survived, but fell into despair, suffering from survivor's guilt, and asking what the point of it all was—to hold off Azmodan long enough for Diablo to return? The Nephalem pointed out that there were still those who relied on him, but he bitterly pointed out that his men had as well, and they were now dead.
The Nephalem travelled to Heaven and returned to Bastion's Keep as necessary. Haile reacted in awe that The Nephalem was still alive. Inspired by their actions, he resolved to do what he could to keep up spirits within the fortress.
The Fall of Westmarch
Haile is encountered in Act III of Diablo III. He is first encountered as an NPC in the quest "Turning the Tide," where the player fights off monsters while his men raise a catapult. In Act IV, he is an NPC in the Bastion's Keep Stronghold hub area.
In Act V, the player enters Captain Haile's home and rescues his daughter Kyla and her friend (a small boy from Bastion's Keep) and helps them escape to the Survivor's Enclave. The player can later find Haile himself in Westmarch, where he helps slaughter a large group of reapers before departing. Captain Haile appears again later on, reunited with his daughter. He happily informs Kyla and her friend that the Reapers have finally been cleared out of Westmarch and soon will be defeated completely.