That might be it, a water bottle that checks your dna every now and then and you use it to login to my game to prove you are who you say you are and not running multiple accounts.
Everyone has to drink all the time anyway!
Now if only those bottles were easy to clean! :P
I have a better idea. Every user must have a holozing tattoo on their right arm to play the game. Each tattoo is unique because it has a certain invisible dot matrix. This way it can be guaranteed that only this body with the respective username can play the game. In this way you can combine ZKP with a continuous check of the user as you can check the tattoo every few hours or days using a webcam.
This was just a joke ;)
We got a patent to do here!