Bann Teagan Guerrin is the bann of Rainesfere. He is Arl Eamon Guerrin's younger brother as well as the brother of Rowan, the deceased queen of Ferelden. This makes him an uncle to King Cailan. Like his brother Eamon, Teagan spent at least a part of his childhood in Redcliffe before he was sent to the north to live with relations in the Free Marches as their father and sister joined the rebellion. He was 8 years old when his father perished at the battle of West Hill.
Immediately after the battle at Ostagar Teagan is shown standing against Loghain at The Landsmeet, highly suspicious of Loghain's withdrawal from the Battle of Ostagar. It seems he is the original instigator of the Bannorn's resistance against Loghain's regency, and he brushes off Queen Anora's reassurances.
When the Warden and party later arrives in Redcliffe, they find out that the city is besieged by undead, and that the seriously ill Arl Eamon is locked in his own castle, with no word from it at all. Bann Teagan is currently in charge of the town's defense and he pleads with the Warden & Alistair (if he's present) to help them defend the city; the Warden can agree or refuse. If the Warden elects to help, Teagan will answer any questions and direct him/her to the Mayor Murdock and the knight Ser Perth.
After the battle, Teagan gives a celebration speech, and asks the Warden to meet him by the windmill for their next move. He reveals there is a secret passage, and did not mention it before as he wanted to help in the battle. At that moment, Arlessa Isolde suddenly runs down the hill to his shock. She insists that Teagan go in with her alone to help her son Connor, speaking of a "terrible evil" in the castle that is behind the attacks. He passes his Signet ring to the Warden, so he/she can take the secret passage and infiltrate the castle while he tries to create a distraction.
As it turns out, Connor is possessed by a Desire Demon, which ensorcels Bann Teagan. After the Warden confronts Connor, a brawl breaks out with the enthralled Teagan and castle guards. After the fight, he regains his senses and retrieves Jowan, who talks of a blood ritual to send a mage into the Fade to attack the demon controlling Connor (unless you elected to let Jowan out of his cell with the comment "Run. I don't want to see you again. Ever", in which case it will be Morrigan who mentions the ritual if she is in your party). After the Warden deals with the desire demon (one way or another), Teagan remains to watch over the Arling while Eamon remains comatose.
Once the Urn of Sacred Ashes is found and Eamon recovers, Teagan stays with his brother at Redcliffe Castle. Later, Eamon orders Teagan to stay with the Redcliffe garrison while he and the Warden go to participate in the Battle of Denerim; however, he brings reinforcements and was not far behind the main body of the Fereldan army: he is seen duelling and killing a hurlock as the archdemon perishes at Fort Drakon, and leads a final attack on the routed darkspawn as the horde flees Denerim.
If the Warden sacrifices him/herself to kill the Archdemon, he will be present at the funeral.
Teagan can end up marrying either Kaitlyn or Bella in the epilogue. If given enough money by the Warden, Kaitlyn will open a foundry at Redcliffe, whereas Bella will start a brewery in Denerim. In either case, the woman becomes wealthy and respected, meeting Teagan at court by chance, and eventually marrying him. A known bug in the epilogue, however, will actually show him marrying both women.
(From the Dragon Age Wikia)
Battle vs Eomer (by Greenberet69)Edit
In the fields of Rohan Eomer comes across the dead body of Theodan while him and his Rohirrim are on a mission to find out what happened to their king. All off a sudden a arrow strikes one off the RohirrimEomer and his men turn to see Bann Teagan Guerrin and 3 Redcliffe soldiers with one reloading his crossbow. Eomer tells his men to mount up and they do and charge at Teagan and his men. The crossbow Redcliffe soldier fires and misses and while reloading a Rohirrim gets out his bow and arrow and fires hitting the Redcliffe soldier. Teagan rders his men to charge and Teagan takes out his Balanced Greatsword and swings it striking a Rohirrim on horseback. A Redcliffe soldier charge at Eomer who uses his spear to stab right through the soldierEomer sees another Redcliffe soldier who tries to take out his last Rohirrim but Eomer uses his spear and tosses it striking the Redcliffe soldier but as the Rohirrim sighs off relief Teagan decapitates him with his Greatsword. Eomer dismounts and takes out his sword Guthwine and a Rohan Shield while Teagan discards his greatsword for his longsword and Redcliffe Shield. Both approach each other and Teagan tries the first blow only to be deflected by the Rohan shield. Eomer tries also to be blocked by Teagan's Redcliffe shield and both try striking one another but keep on blocking each others strikes with their shields. Teagan is able to salsh the Rohan shield out off Eomer's hand but Eomer acts quickly stabbing Teagan in the right leg. Teagan tries to stab him but Eomer quicky dodges and stabs Eomer right through the chest. Eomer yells in victory "For Rohan!!"
While Teagan was a good leader Eomer just had more better weapons armor and training.