you could cut a sheet cake in the shape of the shield. Cover that with MMF or regular fondant. You could paint the shield with powder and lemon juice or a different kind of cake color. Dust it with a silver shimmer. Wilton makes lot of glizzers and shimmers. I would stencel or free hand the dragon on the fondant. It preety easy to draw on fondant. And I would make the sword out of fondant also.
That looks fun! lol
My thoughts for you are as follows (and I am not an expert, so please anyone correct me if I'm wrong here!)
You'll probably have to make your own stencil of the dragon and then use a brush to trace around it. I'd use an exacto knife. The sword looks like it's made out of fondant. As far as the cake goes you could find a drawing of that shield and then have kinkos enlarge it. Then cut it out, place it atop a big cake, and cut away the excess.
And probably purchase stock in shimmer powder stuff. 
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