James Axler is a "house name" (collective pseudonym) used by Gold Eagle Publishing.
The Earth Blood books were written by Laurence James. The Deathlands books were created by Laurence James and Jack Adrian, and mostly written by James until his death. The Outlanders books were created and primarily written by Mark Ellis (1).
Other authors who wrote under the name include Edo van Belkom, Andy Boot, Terry Collins, John Helfers, Rik Hoskin, Victor Milán, Mel Odom, Alan Philipson, Nick Pollotta, Chuck Rogers, and Douglas Wojtowicz.