Mariusz Duda is a Polish musician, composer, vocalist, lyricist, multi-instrumentalist, and music producer. Duda is best known for his performances with the rock band Riverside, one of the most internationally recognized Polish bands, where he served as the main composer, vocalist, bassist, guitarist, and lyricist until his departure in 2026. He is also the creator of the solo project Lunatic Soul and has released solo albums under his own name. With Riverside, he received numerous awards, including Best Anthem at the Progressive Music Awards 2016.