Niklas Sundin is a Swedish musician, best known as a founding member and former lead guitarist of the melodic death metal band Dark Tranquillity from 1989–2020. In 2019, he founded his own band called Mitochondrial Sun, which has released three full-length studio albums to date. He is also a member of Time and the Hunter, a project founded in collaboration with Italian musician Enrico Longhin. He was a guitarist in the metal band Laethora from 2005–2010.