Take now the Pen Tool and insert on a new layer, above the dragon's one a white flare (grouping them preliminary):

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Blur it out a little, selecting the next combination: Filter – Blur – Gaussian Blur.

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Change the dragon's layer Blending Mode on Lighten:

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Select now the Gradient Tool of a darker color than the background is and paint the picture's edges on the layer, above the rays:

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Change now the layer's Blending Mode on Soft Light and minimize the rays' layer Opacity till 90%. In the Blending Options on the dragon's layer we'll add the adjustments Outer Glow, just to place the dragon on the first plan:

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