Gawain
Sir Gawain was a Knight of the Round Table, and King Arthur's own nephew.
To avoid a war, he agreed to marry Lady Ragnell, a repulsive woman in appearance and in manners. On their wedding night, it surfaced that she had actually been under a curse (powered by a shard of the Druse) which made her repulsive until a man agreed to marry her for noble reasons, after which she could choose to regain her true appearance either at night in her husband — at the cost of being ugly in the daylight — or the reverse. She offered Gawain the choice, but he, in turn, told her that it should be her decision alone; this abdication of husbandly sovereignty broke the second half of the curse and allowed Ragnell to remain her true self permanently.
To Donna Noble's disappointment, however, there were limits to Gawain's surprisingly progressive views on female empowerment — as demonstrated when he quite willingly went along with a mob movement to burn Donna as a witch, with Gawain himself very nearly lighting the pyre until the Tenth Doctor (as Merlin) put an end to the attempted execution. (PROSE: Legends of Camelot)
Gawain, alongside Bedevere Agravaine and Galahad, was one of four knights whom Merlin once sent on a four-day journey to slay the Morch'aliach in its cave. Acting as the leader of the expedition, Gawain heavily reprimanded Agravaine when the latter elected to cause a rockslide that trapped the beast in its cave but did not slay it. (PROSE: A Honeycomb of Souls)
According to legend, Gawain would eventually be killed by Lancelot. (PROSE: Legends of Camelot)
