Borusa's regeneration (Arc of Infinity)
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Following the Sontaran invasion of Gallifrey, Lord Chancellor Borusa (TV: The Invasion of Time [+]Loading...["The Invasion of Time (TV story)"]) regenerated into a new incarnation who was Lord President by the time of the Second Omega Crisis. (TV: Arc of Infinity [+]Loading...["Arc of Infinity (TV story)"])
