The Ring is conduit, a way of connecting with the Lucii. Once permission has been granted to wield the power, via blood right or contract, the power remains even if the Ring is passed to another. For example, it's my understanding that Nyx wore the Ring only long enough to make his deal with the Lucii and then passed it to Lady Lunafreya so she could see it safely into my son's possession. Despite handing the Ring off, he was able to use the power until the deal they made was fulfilled.

I'm afraid I've never considered punching people with it. Perhaps, I should have. Doing so certainly would have quieted Aldercapt's prattling during the treaty signing. At least for a little while.