Rollo is the older brother of Ragnar Lothbrok and is played by actor Clive Standen. While Rollo loves his brother dearly, he is constantly battling against the fact that his younger brother is ranked higher than him.
In Season 1 we discover Rollo is in love with Ragnar’s wife, Lagertha. It seems his brother does indeed have everything Rollo wants. As the season progresses, Rollo turns his back on Ragnar and sides with Jarl Borg.
In Season 2, Rollo’s betrayal of Ragnar continues and in the process he manages to critically injure Floki and kill Arne. While it seems his betrayal will result in Rollo’s death he is saved by his brother and descends into depression as he is no longer trusted by his family and friends. Siggy, however, does trust him and they begin a relationship. By the close of this season Rollo has mostly redeemed himself and goes into battle with Ragnar and is almost trampled to death but is saved by Athelstan and King Ecbert.
(Photo Credit: History Channel, Metro-Goldwyn-Mayer Studios Inc.)