He was born in 1958 in Ikaria as the son of father Triandafilos, an Orthodox priest; his mother’s name was Moschoula. In 1979, he moved to Athens, where he worked as a builder and mechanic. In 1983, he met Dimitris Koufodinas who co-opted him with 17th November.
Xiros is regarded as the assassin of Nikos Momferatos, Panagiotis Rousetis, Nikos Georgakopoulos, Dimitris Angelopoulos, William Nordin, as well as an accomplice in the murders of Robert Chad, Alexandros Athanasiadis, Ronald Stewart, Thanos Aksarlyan, and the attempted murder of Yannis Paleokrasas.
Xiros convinced his brother Savvas to join the organization in 1986. On 29 June 2002, Savvas Xiros was arrested for his participation in 17th November, after an explosive device went off in his own hands in Piraeus.
Xiros was apprehended in Evangelismos hospital while visiting his wounded brother. In his testimony, he gave a detailed description of 17th November’s structure and mode of operation as well as of those organisation members he knew. He also admitted his participation in a number of assaults.