Expansion of Treasure Chest subroutine

There's a check for special characters at $C080B4 and character names are taken care at $C080DC. There is also the treasure chest routine after. I made a text centering opcode with one of the dummy one ($17) and just hooked my code in that region since it was directly related to text rendering.

Now that you mention it, I have no idea where the rest of special codes outside those mentioned are taken care of, it's for sure in bank $C0, maybe in the same code region..