Life
Kulun Beg was the last Göktürk ruler who tried to sustain the Second Turkic Khaganate in vain. He succeeded his father Ozmish Qaghan who was killed by the Alp Bilge.
He was enthroned in 744. When he was enthroned the Central Asian steppes were already conquered by the Uighurs. Alp Bilge was deposed by Kutlug I Bilge Qaghan of Uighur Khanate. Although Kulun Beg tried to escape from Uighurs to gather new army against them, he was arrested by the Uighurs and was beheaded in 745.
The story of Turkic Göktürk Khaganate ends here... Uighurs destroyed Turkic Khaganate. Uighurs are also a Turkic people but they were enemy of Göktürks anyway. Turkic Khaganate destroyed by Uighur Khanate and later Uighur Khanate destroyed by Yenisei Kyrgyz Khanate. Turkic states destroyed Turkic states in Central Asian steppes.