Where can I get a radiant sword badge?

I'm curious, where exactly can one acquire a radiant sword badge? Is it a unique item found in a specific game, or perhaps a collectible from a renowned artist? If it's tied to a particular event or quest, could you elaborate on the steps required to obtain it? And lastly, are there any limitations or restrictions on who can claim this elusive badge? I'm eager to learn more about this fascinating item.