User blog comment:ClariS/Why Xerath's Passive is Bad/@comment-82.17.44.13-20130317162946/@comment-4881935-20130317164920

Well, to be fair for Kass, Kass is required to jump next to an enemy. His magic reduction makes sense a bit regarding the risk he has to put himself in.

But yes, and Xearth is not even that immobile thanks to his bonus movement speed on his W. That will allow him to reposition himself and keep himself at a distance against the enemy team.