Habd was a retired Redguard sailor.
Habd bought Frostflow Lighthouse to live in with his wife and children. Several days after, noises began coming from the cellar, so he went to the town to buy some traps. Returning, he found his wife dead and a chaurus, which he killed.
Desperate, he hoped to rescue his children, locking himself in the cellar so that the Chaurus couldn't get past him to the surface again, but was captured by the Falmer. By this time his son had been killed and his daughter had also been captured. His rescue attempt was a failure, and he contracted a fever through Chaurus poison. Delirious, he left an iron dagger to his daughter when he was taken away.
The Dragonborn comes into the story too late to actually help the family. However, picking up a clue before entering the cellar, they can at least make Habd's final request occur.
The Dragonborn may find his decomposed remains inside a Chaurus Reaper and throw them to the fire at the top of the beacon, so Habd can see the sea forever as he always wanted. This grants the Dragonborn the Sailor's Repose active effect.