||Desmond David Hume, played by Henry Ian Cusick
Desmond, a former military man, found himself on the island after his sailboat wrecked there during a storm on his "race around the world." After being "drafted" into the Dharma Initiative's dealings in the Swan Hatch, he was kept inside the hatch for nearly three years by his "partner" Kelvin, who was planning to leave the island in Desmond's refurbished boat. In rage, he accidentally kills Kelvin.
Desmond meets the survivors after they blow open the hatch, and when the "108 minute button" is destroyed, he abandons them in favor of escape on the boat. Two weeks later, he finds himself back on the island---and back in the hatch, eventually blowing it up. While Desmond survived the destruction, it appears he either has had or recently aquired the ability to "glimpse" into the future.
Desmond is a man who's in search of his honor---he "lost" this by being sent to military prison and later dishonorably discharged (though we don't know as of yet what the charge was). His only wish is to be reunited with the love of his life, Penny Widmore---the daughter of a very rich and powerful man who wants Desmond erased from her life.