Map Fn + Esc key to Esc key I am using a PC keybroad on a Mac, the funniest thing is on this KB, to use the Esc key, I need to press Fn + Esc

So, are there any tool I can remap the keys such that I can use the Esc without the Fn key?
Fn is a function of the keyboard that modifies the key-codes being sent by the keyboard itself. Fn itself does not transmit any key-codes to the computer.

One option would be to try mapping the actual key (that is turned into Esc when Fn is pressed) to be the Esc key. I don't know of anything built into OS X that will do this across the board, however, you could try something like https://pqrs.org/macosx/keyremap4macbook/

To be honest, good keyboards are so cheap these days you should probably just buy yourself a nice new keyboard that has a layout which suites your needs better.