The Diamond Knight, or the Diamond Enthusiast is a knight with armor of great proportion. The glare of sunshine off his diamond - coated chestplate blinds his enemies and renders their sight useless. When he charges into battle, his enemies tremble in fear of having their eyes sunken by glancing at his amazing armor.

tl;dr: SHINEEEEEEEEEY

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http://www.planetminecraft.com/blog/the-enthusiasts-skins/