Dragon Knight is a melee strength carry who is able to maintain a presence at all stages of the game, which has made him a popular and stable pick in the competitive scene for quite some time.
He has access to early burst magic damage, is highly tanky, and is very strong in the mid and late games thanks to his ultimate, Elder Dragon Form.
Skills
Breathe Fire is always maxed first.
Dragon Tail is always skilled first but usually maxed last.
Dragon Blood is usually maxed second.
Elder Dragon Form is always skilled (levels 6, 11 and 16).
Items
Starting Items: Tangos, Quelling Blade, Gauntlets of Strength, 2x Iron Branches.
Early Game: Power Treads (or Phase Boots), Magic Wand, Bracer.
Core Options (Pick One): Helm of the Dominator, Black King Bar, Shadow Blade, Maelstrom.
Luxury Items: Drums of Endurance, Assault Cuirass, Mjollnir, Daedalus, Heaven's Halberd, Satanic, Heart of Tarrasque, Monkey King Bar.
Situational Items: Soul Ring, Bottle, Hand of Midas, Boots of Travel, Divine Rapier.