This paper summarizes our history with designing coherent real-time processing algorithms within Kyma that enable the spontaneous processing of acoustic instruments using the Capybara-320 and Pacarana synthesis engines in interactive real-time performance. Compositional and performance issues for the current work, System of Shadows, are examined, discussed, and performed during the demonstration, focusing on the composer’s Kyma processing algorithms and the musical score used by both performers. We posit relevant data surrounding the interactive performance issues involved in a complex real-time processing work of this nature, and discuss our collaborative creative process. Real-time performance choices by the trumpeter, directed improvisation and interaction between the two performers (and the formal compositional structures these decision help shape), realtime programmatic choices, and Kyma’s virtual control parameters are discussed in the context of the larger dynamic performance environment.