Ubbe Ragnarsson was a formidable 9th-century Viking leader, son of the legendary Ragnar Lothbrok, known as a key commander of the Great Heathen Army that invaded England, characterized by fierce determination and leadership in battle, though his historical image blends with fictional portrayals emphasizing loyalty, strength, and a desire for exploration, ultimately meeting his end at the Battle of Cynwit.

Historical Ubbe:
Leader of the Great Heathen Army: A central figure in the Viking invasions of England around 865 AD, alongside his brothers Ivar the Boneless and Halfdan.
Avenger of Ragnar: His campaigns were driven by a desire to avenge his father's death.
Fierce Warrior: Described as a formidable and ruthless commander, a force of nature in combat.
Death at Battle of Cynwit (878 AD): He was defeated and killed by West Saxon forces led by Ealdorman Odda, a significant blow to the Viking cause and a turning point in the English resistance.

Fictional Ubbe (in Vikings & The Last Kingdom):
Grounded & Wise: Often portrayed as more level-headed, pragmatic, and morally grounded than his brothers, seeking balance and exploration.
Diplomatic: Shows strength in diplomacy, alliance-building, and a vision for a future beyond constant warfare.
Exploration & Discovery: Embarks on voyages to new lands (like North America), driven by adventure and a search for peace, reflecting Ragnar's curiosity.
Loyalty & Family: Deeply committed to his family and their legacy, adding complexity beyond a typical brute warrior.

In essence, Ubbe is a complex figure: historically, a powerful Viking warlord whose death marked a shift in the Anglo-Saxon struggle; in popular culture, a more nuanced hero embodying the spirit of exploration and moral strength.