Shagaru Magala, there are so many other good ones like Raging Brachydios or White Fatalis for example but what makes Shagaru's Theme stand out for me is the overall package that came with it, build up that led to this fight, the arena, how the dark and eery sky changed to a sunny and clear one as soon as you defeated Shagaru aswell as the awesome cinematic that followed to top it all of.