Hanssa was a devout paladin of Dava, active towards the end of the Third Age. She was a righteous protector along the West Sea coast, and many say that she's the reason there is a profound lack of the undead here.
She met her untimely end on a place then called "Beerman's Bite" where her temple now stands, where boatmen (probably smugglers) complained of haunted caves and horrible sea monsters. For many years most sailors ignored it, thinking it to be pirates or myth, and simply hugged the coast when approaching the tiny harbor to offload goods destined for the Northern Kingdoms.
As the story goes, ancestors of the Markand family were expecting a very valuable delivery to arrive and had a caravan at the coast awaiting its arrival from Faerethel. After waiting several days, and almost giving up hope, wreckage began to wash ashore. Among it, a lone halfling sailor who told a tale of a horrible creature which dragged the ship and most of its crew to the depths. Furious, the family called on the local nobles to help resolve this mystery, and Hanssa heard the call of duty.
She traveled to the island with a small party of pilgrims and there she indeed found the scraps of the ship, and then picked clean bones of its crew. She camped there for 12 days, praying that Dava would show her what to do. And a vision came, showing a terrible creature which would devour any ship that came; spawn of the very Kraken itself.
On the 13th day the beast appeared, scattering the pilgrims and terrorizing all that saw it. Hanssa, without fail, took up her sword and attacked what portions of the beast she could see, fighting it with all her might but in the end, a great maw appeared and swallowed her whole.
The survivors cowered fearing for their lives but documented seeing a bright light from within the beast, shining like the light of the sun, wherein it burst into flame and was seen no more. Hanssa's war cry echoed over the water and the folk knew surely that she'd saved the coast.
A single Davanic priest, Ebel the Pure, returned with a few of the remaining pilgrims to write her tale. The High Priest at Glimring, reading it, confirmed that he'd seen a vision in his dreams of the very fight and cannonized her as a saint on that day. However, miracles begin to happen along the lower coast, and the fisherfolk of the area declared it must surely have been Hannsa.
From that day forward she has been treated as a demigoddess, occasionally granting powers to certain worshippers, seemingly on a whim. The only true cleric which called on her power was one Estra Cleverknot, who became high priestess of the faith and established the current shrine about 300 years ago.