If you use someone else's IP and don't try to hide it or change it any, you can be a target. But it may depend on how much the owner of the IP wants to spend to go after you.
If for example you have a game using their characters that pulls up on the first page of Google if people search for the original IP holders stuff, you're probably going to get in trouble soon.
If you use a character the IP holder viciously protects with every ounce of their legal means, like Sanrio, if you even come close to the art style of that character they will come after you.
So it varies. I think overall if you have the talent to make a game, have the talent to make an original character and setting that won't cause problems for you later on down the road. Just start original and go from there.