I’m trying to create a magical artifact of intense power for my campaign.

I’m trying to create a magical artifact of intense power for my campaign.

I’m trying to create a magical artifact of intense power for my campaign. It’s called “The Architect’s Rod,” and the purpose of it is to generate massive buildings, castles, and even cities. However, I’m not sure what the rolls would be for this, or any of the mechanics. It’s an interesting concept and I’m sort-of already working it into my campaign. Help?