  In this article, we describe the underlying reduced scheme of a quaternionic
unitary Rapoport-Zink space with Iwahori level structure. In a previous work,
we have studied the quaternionic unitary Rapoport-Zink space with a special
maximal parahoric level structure. We will describe the morphism between these
two Rapoport-Zink spaces and the fiber of this morphism. As an application of
this result, we describe the the quaternionic unitary Rapoport-Zink space with
any parahoric level structure.
