Previous research on phase separating metallic glasses (PSMGs) suggests that exploring these paradigm shifting materials would be very fruitful for design of new types of composite structure. Thus, PSMGs have been actively studied not only to understand conditions for separation but also to investigate their unique properties. However, there has been no systematic approach to understand the role of secondary amorphous phase (SAP) in these PSMGs. In this study, we examine the effect of SAPs on their properties in various metallic glasses. We can fabricate SAP with different sizes in glassy matrix by controlling the kinds and amount of additional elements. Firstly, we will provide systematic discussion of the relationship between atomic scale SAPs and shear band formation. Secondly, we will discuss how nanometer scale SAP containing magnetic elements influences magnetic properties in PSMGs. Our results would contribute to a deeper understanding of various roles SAPs play in glassy matrix.