Beybolat Bey

Hier to the beylik of the Umuroglu tribe, Beybolat bey, later revealed as Albasti, is a traitor and protagonist in Season 5. He allied with Alincak to overthrow Ertugrul, but fails and is later killed by Ertugrul.Beybolat works as an assassin, teamed with the Mongols to remove certain Oğuz Tribes, under the fake name Albaşti. He is mentioned as the killer who attacked Gundogdu's tribe off-screen.

Role
His character is similar to that of Ural bey. In the show, Beybolat is the second treacherous brother, the first being Ural. Both have a rightful younger sister, who marry into the Kayi Tribe. Both men were also willing to remove their fathers for their job.This is shown during a conversation with Beybolat and Alincak, when he explains that he would kill even his father, to keep his position as Albasti. However, despite rebelling against their state, neither have changed their religion for the sake of the Mongols.

Umur bey
Beybolat was shown to be close to his father, as after his murder he was left furious. Determined to find the murdurer, he teamed with Dragos, not knowing he was working with his very father's killer.

Ilbilge hatun
After her father's death, Ilibilge was convinced Ertugrul was to blame. She had a steady relationship with her brother until she allied with Ertugrul, as he uncoverved her father's real killer. Their friendship angered Beybolat, but kept it hidden whilst he schemed with Dragos. When Ertugrul proposed to her, Beybolat was shown to accept it, but when his true colours were shown, their relationship shattered. Ilibilge truly cared for her brother, but was ready to have him punsihed for the sake of justice. After his death, Ilibilge was saddened, but quickly accepted his fate.

Sirma hatun
Being the youngest of the siblings, Sirma was shown to be naiive, and loving to her siblings. She and Beybolat had a good friendship, as she plotted with him. After his death Sirma was most appalled, and surprised to hear of his hidden name, Albasti. Her love for her brother was shown as her eagerness for revenge grew, forming an alliance with the Mongols to destroy Ertugrul. She was later stabbed and buried next to her crime partner and brother.