3D Modeling The Witch King of Angmar sword - Need Help!

I am making the sword the Witch King carries in The Return of the King. It looks like this:



I am printing the cross guard, handle and pommel and attaching them to a wood blade I will make. I am modeling it to fit around a 16mm steel tube for support. Being new to 3D modelling I am able to get the basic shapes and have got this far:



Anyone with more experience able to give me some insight into adding the details like this bit:

I have very limited knowledge but I have used inkscape (freeware) to trace a screenshot etc to create a .svg file. You can then import into your modelling software (I use fusion360) and use it like a normal sketch to extruder/cut the design.
Or you can import an image to fusion as a canvas and sketch splines over the top of it.

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