The most significant change in Armageddon's Blade is the addition of the Conflux town, bringing the total number of alignments in Heroes of Might and Magic III to nine.

[4] Following the death of Xenofex, a usurper named Lucifer Kreegan takes control of Eeofol and, driven by a vision, begins to seek a means to fashion an ancient weapon known as Armageddon's Blade, capable of setting the world on fire.

To stop him, the armies of Erathia and AvLee launch an attack on Eeofol, unexpectedly receiving assistance from servants of the Lords of the four Elemental Planes in the form of the new Conflux towns that have mysteriously appeared.

"Dragon Slayer" features the Bracadan wizard Dracon, while "Festival of Life" introduces the Krewlod barbarian Kilgor, who has a prominent role at the outset of Heroes of Might and Magic IV.

Finally, the unlockable "Foolhardy Waywardness" campaign features the knight Sir Christian, who also returns in Heroes of Might and Magic IV.

[10] Midway through the expansion's development, New World Computing decided to scrap the Forge faction and removed all references to its existence from the game's storyline, instead building upon Might and Magic VII's "good" ending.

[11] Due to the scrapping of the Forge halfway through the project, the developers and design artists suffered from a lack of time when completing the Conflux faction, and were forced to implement elemental creatures from the base game.

[12] IGN's Rich Rouse noted improvements made to the map editor and praised the amount of new content,[20] while GameSpot's Andrew Seyoon Park focused on the addition of the Conflux alignment and subtle tweaks to the gameplay.

[17] GameRevolution's Duke Ferris was mildly disappointed with the Conflux town and its use of neutral creatures already included in the base game, but praised the campaign storyline and gameplay along with the addition of new features.