ixo is not running on Ethereum - ixo protocol is built on the Cosmos SDK & runs its own network.
ixo is not a PoW protocol - ixo is built on the Cosmos SDK, a PoS protocol.
ixo is not open to anyone - anyone can join the network in read-only by setting up a node, but one must be vetted in order to be able to write to the network (become a validator). This type of blockchain network is often called public-permissionned.
Feeling lost? you might want to start reading here Welcome to the ixo forum - START HERE