Kill Bann Teagan is a side quest in The Darkspawn Chronicles DLC for Dragon Age: Origins. It is available as part of the main quest Massacre in the Market. Kill Bann Teagan and his men.
Walkthrough
Proceed to the southwest area of the Market District, to the small courtyard outside of the Arl of Redcliffe's Estate. Kill Teagan and all of the guards.
Reward
Redcliffe Shield, dropped by Bann Teagan.