Omniknight is a melee character. His primary attribute is strength. The hero is mainly taken as a support. Most effective in the early and mid game.
Omninight is able to save allies in almost any situation. Hammer of Purity allows the hero to effectively trade blows in the lane, while Purification and Heavenly Grace make it difficult for enemies to quickly defeat Omninight's allies. Purchasing Aghanim's Shard grants the Degen Aura passive ability, which is useful when chasing enemies. Aghanim's Scepter upgrades the Guardian Angel ultimate ability allowing it to ignore all physical damage and making the hero useful in long-range fights.
Purist Thunderwrath served an order dedicated to deeds in the name of Omniscience. After years of sacrifice and loss, he lost faith, but Omniscience returned it, and now the paladin's campaign had meaning again. You can be sure that behind his healing abilities and military courage there are real forces, and not some fiction.