You can't build something like that directly on Hive. Think of Hive as a big decentralised storage. You can put all kinds of data on there, but in order to use it, you'll need to create applications which read from and write to the data.

In order for the user to be "online", you'll need to utilise real-time frameworks (i.e. https://colyseus.io/ - which I'm using for both Ethgard & Ethgard Legends). When the user changes maps, opens chest or defeats a monster, you could update the data onchain, but you will always need an offchain application layer between Hive and the user.