How exactly does registered trademark law works?

Intellectual property rights are territorial. American trademarks, patents and copyrights, therefore, do not confer protection on their owners in Europe if the IP owner has not registered their product with your nation’s patent office. The sole exception to this rule involves trademark applications filed under the Madrid Protocol. This system permits American business owners to submit trademark applications that protect their mark in the United States and other designated nations. If the trademark owner in your case did submit such an application and paid for IP protection in your country, you would be prohibited from using the mark.

Trademark Law Firm in Vietnam

Finally, I would strongly encourage you to research whether this comic book trademark is protected intellectual property in Europe. I say this only because the registered trademark symbol ‘(®)’ can denote a trademark in a country other than the United States. The comic book image could, for instance, be a registered trademark in Vietnam. You do not want to inadvertently violate any IP laws.