Serenity is a CCP server cluster that exclusively serves EVE Online's Chinese playerbase and hosts an entirely separate instance of the EVE Universe that is not influenced by activities on Tranquility. It is one of two production server clusters that CCP operates, alongside Tranquility. Accounts on this server are specific to the cluster, and cannot interact with players of other server clusters, much like how actions on Singularity do not affect those on Tranquility.
Due to the separation of players between the two production server clusters, there are separate characters, corporations, and alliances between the two, and while some corporations and alliances share a presence on both server clusters, they are separately managed. Sovnull on Serenity is also in a different state at any point compared to the state of sovnull on Tranquility, with different alliances holding different systems and regions.