The rarity of Hammer of the Purist Champion is Uncommon. At this moment the item is available for trade.
Hammer of the Purist Champion is a skin for Omniknight. The skin was added to the game on Invalid Date, it was created by Vladimir >the implyer.
Hammer of the Purist Champion is currently one of the most popular skins, but it is rarely seen in the game due to its high price.