Bann Teagan is the Bann currently in charge of Redcliffe. Possibly he's Arl Eamon Guerrein's direct subordinate.
Background
Involvement
When the Player Character and his party arrives in Redcliffe, they find out that the city is beseiged by undead, mainly Devouring Corpses, that Arl Eamon is locked in his own castle and Bann Teagan himself currently in charge of the town and it's defense. Bann Teagan pleads with the Player Character to help them defend the city which the Player Character can refuse or consent to do.