Kuber was a prominent Bulgar leader in the 670s, known for his pivotal role in liberating a diverse population of Bulgars and Byzantine Christians. This community had its roots in the Eastern Roman Empire, having been relocated to the Syrmia region in Pannonia by the Avars approximately sixty years prior to Kuber's leadership.
His actions were notably chronicled in the 'Miracles of Saint Demetrius,' which highlights his commitment to the welfare of his people. Kuber's leadership was marked by a desire to restore autonomy and dignity to those who had suffered under foreign rule.
Scholarly theories suggest that Kuber was the son of Kubrat and the brother of Khan Asparukh, positioning him within the influential Dulo clan. This lineage not only underscores his noble heritage but also his significant role in the historical narrative of the Bulgars during a transformative period.