Re: Character for comic and game. Copyright issue?
Trademarks require that the holder do Due Diligence to defend it or they lose it. If they sue someone for infringement and that defendant can show that they failed to go after someone else similarly infringing (and it was known to the plaintiff they were infringing), then they have to pursue the other person first before they can proceed on the lawsuit against the current person.
You might find it stupid that they'd sue over this, but the law actually requires them to.
Intel sued a Yoga studio for creating a logo that was Yoga Inside for infringing their trademarked slogan of Intel Inside. The suit went nowhere, but it still became a matter of court record that Intel had done its due diligence (and the Yoga studio got to soak the legal fees to defend themselves).