Kind of an odd event that still combines very well with multiple Shadow Elves tactics. In part because thanks to your Mages and Knights, gates on both sides will end wounded more often than not. 
Shadow Pulse is a great event on defense, allowing you to soften up aggressive armies. It’s also good to punish armies that cluster around their own gates and can often help you finish off a wounded summoner hiding from Selundar.

Have in mind that you can damage your own gates to get Selundar’s Boosts.