Would you like tea and cake as well?

As a word of advice, "I need code for X" isn't going to get you much good help in these forums. Your request is too vague. Nobody really knows what you're trying to accomplish, so the only way you'll get help is to explain what you're looking for in detail. A "follower system" could mean all kinds of things, and a bump proc can involve any number of interactions. Battle systems tend to be unique to each game because they require design decisions to be made.

No doubt you have many of these ideas fleshed out in your mind already, but you'll need to give people as precise a picture of them as you can. I think you'll find it easier if you try to tackle each of theses subjects by breaking them down into smaller pieces. For instance, any of these questions (or variations on them) would work better and get you closer to your goal:

"I don't understand how to cause damage to something when I bump into it. Can someone show me how?"

"If I have a few other mobs with me in a group, how can I make sure they'll follow me around?"

"I'm trying to create a battle system where players take turns choosing actions, like in a JRPG. When one bumps into the other, I would like to start the battle and transport them both to an arena, have them take turns, then return them when the battle is over. Can anyone give me any ideas as to how to do these things?"

That last question is actually asking how to accomplish several things, so that can be broken up into still more steps. But the good thing about it is, it's clear and spells out exactly what kind of help the person is looking for. That kind of approach will help you.

Lummox JR

Not all people have played all games. Just Spit your intention. with required specifications.