X-O Manowar #21 was published by Valiant/Acclaim on June 1, 1998, as part of a series that began in 1997. Dwayne McDuffie writes, and art comes from Atomic Paintbrush, Don Hudson and Scot Eaton. This 36-page issue features Quantum, Woody, Russ Magnus, Joshua Fireseed and Ninjak, among 10 characters cataloged on VerseDB.