Nirvana is Self realizing it itself is the Eternal One.

False imagination teaches that such things as light and shade, long and short, black and white are different and are to be discriminated; but they are not independent of each other; they are only different aspects of the same thing, they are terms of relation, not of reality. Conditions of existence are not of a mutually exclusive character; in essence things are not two but one. Even Nirvana and Samsara's world of life and death are aspects of the same thing, for there is no Nirvana except where is Samsara, and no Samsara except where is Nirvana. All duality is falsely imagined.
~ The LaαΉ…kāvatāra SΕ«tra