What are original AI characters?
Original characters don't come from a novel or a show. They were written for DokiPal, some by us and some by the people who use it, so nobody knows the ending yet.
That makes them the easiest place to start if you haven't read anything. No canon to catch up on, no fandom to get wrong. The yandere who kept every letter, the treasurer who covers your budget in secret, the butler who disapproves of your posture: each one arrives with a situation and waits to see what you'll do with it.
Because nobody else owns their story, it can go wherever you take it. Some are gentle and some are trouble; the tags tell you which before you say hello. When you're ready, you can write your own.