He's a Lion knight. No... not those new Lion Knights. This fellow belongs to the oldest Lion Knights in the LEGO Castle genre: the 1984-1992 Legoland Castle "Lion Knights."
Of course, as you can see, this guy isn't straight out of a contemporary set, but a customized fig. He's made an appearance on the Internet before, as the rather minor character of Sir Edmond of Orimault, one of Princess Anne's suitors in the early chapters. His sword, helm, and breastplate comes from the now-defunct Little Armory, one of the earliest commercial LEGO customizers.
However, as you can see, the customization on Sir Edmond is not limited to what the Little Armory products I gave him. The pennant on his lance, his shield, and his torso all bear customized arms--based on the gold-rimmed classic Lion shield seen on this torso, and it is by limiting myself to these two colours (with the addition of greys and blacks) that we get this distinctly non-traditional Legoland Castle Lion Knight--a faction that defined itself by wearing red in opposition to its opponents, the Black Falcons.
Although I created the actual stickers seen on Sir Edmond, the templates were based on those created by Anthony Sava on Classic-Castle, and would likely not have appeared without them.
Also, in other news, look forward to daily updates from Aquazone Breakfast News over the next twenty-four days. Starting tomorrow, they present the 2011 City Advent Calendar!