When the IP holder whose characters you rip off feels like it, their lawyers can cause you all kinds of legal trouble. Copyright and IP lawsuits are civil lawsuits, and in civil lawsuits it's not about who is right, it's about who is right and has enough money to prove it.
Even if we assume the best case and a court ends up deciding that all their claims are ridiculous, this will be after you paid a fortune in legal fees and after various injunctions, subpoenas and DMCA takedown notices have already ruined your business.
Instead of ripping off someone else's IP, better develop your own. It's far safer and it's more fun anyway.