This addon lets you fight online against other players with this addon. *KIND OF
It does not let you fight live against eachother but it allows you to fight basically the character save of another player.(or one of your own characters)

What it does do is register the way you play, what moves you make and how you react. Then it tries to mimic this when fighting others.
You will recieve a arena shard at lvl 5, if you use this you will be teleported to the arena.(only out of combat)

In this arena you can upload your character to fight others and challenge other saves.
There are leaderboards, and an Elo ranking system which you can all see ingame.
I have also made a website where you can register your "champion" and see how he does, and see other rankings etc.

• IMPORTANT

Registering on the website is completely optional, and it does not take your e-mail or any other data. You register through the game itself, so i can ensure it only takes data from the game and nothing else.
If you want to check it out the website is tomeoba.com

I originally made this for the monstermon addon (which has this but for trainers only and you can duel other trainers),
but with a few tweaks i got it working as a standalone system with the basegame.

THIS SHOULD WORK WITH OLD SAVED

A quick and easy mod to remind you to get your hind quarters to Derth if you haven't already by level 13!

You cannot enter anywhere except Derth if arena quest isn't completed when player reach level 10.

Adds steam generators, medical injectors, steamguns and steamsaws to the Arena shop. NOTE: This overoads stores, so I do not recomend using it for anything else than Arena runs.

Shoves you into the Infinite Dungeon after winning The Arena.

It gives you a Transmog chest, and unlocks leveling, worry not.