Buddha's realisation was that Mara or Satan was an aspect of himself, his own negative aspect.
We all have a dark side, symbolised in Eastern Literature as the dark form of Diti. Only after we conquer our negative aspect, can we hope for Self Acutalisation.
I walk on the Razor's edge alone,
The path is narrow, the way Unknown !
So let us embrace Universal Love, Universal Brotherhood and Friendship. Let us remove our negative aspect and embrace all of humanity and Nature in her beauty, as Einstein said !
Yet till evil is slain in its own house
And Light invades the world's inconscient base
And perished has the Adversary Force
He must still labour on, his work half done !