Omniknight is a melee strength support hero. Unlike most supports he lacks lockdown, but what he does bring to the table is an incredible healing bomb as well as both magical and physical damage immunity abilities, making him a defensive support beast in teamfights.
Skills
Purification is always skilled and maxed first.
Repel is skilled and maxed second
Degen Aura is skilled and maxed last.
Guardian Angel is always skilled (levels 6, 11 and 16).
Items
Starting Items: Observer Wards and/or Courier, Tangos, Healing Salve, 3x Iron Branches, Clarity.
Early Game: Flying Courier, Observer Wards, Boots of Speed, Magic Wand, Bracer.
Core Items: Arcane Boots, Mekanism.
Luxury Items: Aghanim's Scepter, Drums of Endurance, Heaven's Halberd, Eul's Scepter of Divinity, Force Staff, Ghost Scepter, Refresher Orb, Scythe of Vyse, Shiva's Guard.
Situational Items: Boots of Travel, Vladmir's Offering, Pipe of Insight, Necronomicon, Soul Ring.