Although I'm very aware that there is a thread already about this, I have a different way to look at the issue plus some surprising information.
If you google "Karma Koin", within the first few pages of results you'll end up at a USPTO (United States Patent Trade Office) scraper which pulls public information from USPTO and makes it available for consumption. Here's the link for all trademarks that Nexon America owns:
You'll notice here that they applied for a Karma Koin and Karma trademark. The Karma Koin trademark was refused on a technicality regarding whether it was a magnetic card or not, but the intent to trademark the term is well-intact. There are also other trademarks there for which I couldn't find an immediate purpose, most notably Zombie Misfits and Wonder Cruise. Anyone know anything about those?