The phrase "ultimate manifestation" refers to the highest or most complete representation or expression of something. It indicates reaching the peak or pinnacle of that particular thing. Full definition
RUSH is the game's ultimate manifestation of boost and power that allows you to wreak havoc on your opponents and take control of the race.: (mkaugaming.com)
When read this way, the cross is not the ultimate humiliation of Jesus, but the ultimate manifestation of the divinity of God in Jesus. (redeeminggod.com)
It arises directly out of the primitive Christian valuation of the facts of history and experience as eschatological facts, that is, as the ultimate manifestation in time of the eternal counsel of God. (religion-online.org)