Giving Lore to Another Character

Actually, cheats generally overwrite a game's RAM information - like savestates. It's similar, but a little different from the ROM hex editing that Poco's talking about.

Editing RAM just changes things as you're playing. Editing ROM changes the source code that performs all the functions. Most cheats are just editing RAM (because it's easier, but not a permanent, and often times, not a stable change).