With the release v0.10.0 on August 10, you’re now able to withdraw your Zee as ERC-721 NFTs on Arbitrum and trade them on OpenSea and the Trove marketplaces!
Once withdrawn, your Zee will appear in your wallet along with metadata on their level and attribute strength.
When a Zee is sold or transferred, it will incur a 12 hour cooldown period before it can be used in battle. And keep in mind that the game will enforce you to always keep at least 1 in-game Zee in your inventory to prevent strange scenarios with players having no Zee on their team.