Hm. Doesn't look too bad, depending on your target poly count you might lose or have some blurring of the sculpted details on the sword scabbard in particular. If you have too many problems I'd be willing to give it a go but I can't say how long I'd take to do it. All things considered decimation and auto retopo is very fast. Seriously, download instant meshes, spend 15 minutes familiarizing yourself, do some trial runs with iterations of lower vertex count targets and perhaps edge flow manipulations with the brush/comb tools if necessary, and find what you like. It should only be a matter of a couple hours of playing around, and that's a very "making allowances" estimate, to get something reasonable. I'd start with a reduction of about half of the vertex count to start and go from there.