Warlord of Mars adapts the original stories from Edgar Rice Burroughs from the first 3 Barsoom novels: "A Princess of Mars," "The Gods of Mars," and "The Warlord of Mars," from issue #1 through #18 before starting original material.
There is a numbering gap in this series in between issue #35 and #100. Dynamite Entertainment jumped ahead to #100 by counting all of the other Mars books they had produced to date, including Warlord of Mars: Dejah Thoris, Warriors of Mars, Warlord of Mars: Fall of Barsoom, Dejah Thoris and the White Apes of Mars, Dejah Thoris and the Green Men of Mars, and Warlord of Mars Annual. They did not count the Warlord of Mars/Tarzan crossover Lords of Mars in this numbering.
Beginning with issue #28 the book carries a note on the indicia page stating "This book is not authorized by Edgar Rice Burroughs, Inc."
The story from this series continues in Dejah of Mars #1.