A key issue noted for First appearance of Blacksun. Marvel Two-in-One #21 was published by Marvel Comics on November 1, 1976, as part of a series that began in 1974. Bill Mantlo writes, and art comes from Janice Cohen, Joe Sinnott and Nathan Walker. This 36-page issue features Iron Man, Thing, Human Torch, Doc Savage and Monk, among 7 characters cataloged on VerseDB.