Well, as the title would indicate, this is about attaching armour plates... To fabric.

The character I'm cosplaying is Ragna the bloodedge who has six armour plates on his red coat, two on each sleeve and then a pair of longer ones on his waist. Since the art doesn't really show how they are attached, does anyone have any suggestions on how to attach them?

If you want them removeable I would hot glue velcro onto the armour plate and sew the soft velcro parts onto the coat.

Velcro might be an idea, but knowing my luck, they'd probably go missing all the time. Thanks for the suggestion, and I'll definitely keep it in mind.

Another option is to hot glue some folded over fabric into the insides of the armour parts and then attach to the costume by tack stitching through the coat and into the armour fabric..

Thanks very much. That ended up being the method I used in the end and the armour seems rather secure there. Also bought myself some UHU glue if it needs repairs. Thanks again.