Thiaderd when encountered
Thiaderd is a character shortly involved in the storyline of Viking Conquest. In the story, he has started a Friesian rebellion to overthrow their Danish masters so that Friese can be an independent nation. Jarl Hrodulf Haraldsson sends you to kill him and put an end to the rebellion.
You can choose to talk to him beforehand; however, Reginhard, one of his former subjects, will try to talk to him as well which will anger Thiaderd and cause the rebels to attack you. The reason for this is that Reginhard used to be a rebel but betrayed them to Jarl Hrodulf Haraldsson, which ultimately led to the torture by blood eagle and death of Thiaderd's brother.
After his death, along with his army, the player decides what to do with the families of the rebels. Reginhard shows great remorse for killing them, stating that they were good people and that this all wouldn't have happened if he hadn't betrayed them.