LUNA is an ERC20 token used in Lunacia for in-game purchases and fees. LUNA may be earned by using Axies to harvest resources from nodes, defeating bosses, winning tournaments, creating content, charging other users to access land in Lunacia, etc.
LUNA is not yet available on any exchanges. ForkDelta claims to allow traders to use their exchange with any ERC20 tokens available on the Ethereum network. The Luna token can be traded here: https://forkdelta.app/#!/trade/0x92bf969865c80eda082fd5d8b4e28da4d58e1c3a-ETH
Please do your own due diligence and trade carefully!