This is a replica of Leo's cloak clasp from his Dark Crusader promotion in Fire Emblem Warriors. It has a flat back to allow for a variety of clasps and closures to suit your costuming needs or could be easily modified to sink them into the back for a neater finish.
I intend to test out a few filaments and finishes, but Amolen's Frosted Bronze PLA matches my armour nicely, as does a few coats of XTC-3D with brass powder.
The STL may be a bit undersized when imported for slicing, I print it at 90x52x9.4 to match the sizing of my armor. I left it at the Cura default 20% infill but it can likely be tweaked.
This model was made in Blender as a learning project. It was extruded over a screencap to match the outline, then the raised design was made separately in the same fashion. The design was deformed using a lattice so that it curved with the surface of the base and they were joined afterward. Both were treated with a level 6 subsurface modifier to render them super-smooth. Overall, it was a good learning experience that I hope a few others can benefit from!