The Mastodon is a heavy assault transport built for the Space Marine Legions during the Great Crusade and Horus Heresy. It’s the biggest troop carrier the Legiones Astartes had, and it was only sent in when a fortress absolutely had to fall.
What the Mastodon actually is
It’s a heavy tank, much larger than a Land Raider, and it exists for one job: punching into the most heavily fortified positions an enemy can build. Every Legion had some by the later Great Crusade, but they were rare and used sparingly.
The Imperial Army’s Old Hundred regiments used them too, so it wasn’t purely a Legion asset. The Salamanders are the famous example: at the start of the Kharaatan campaign they had enough Mastodons to move their entire deployed force, roughly 6,000 Legionaries.
Why it matters
The Mastodon’s party trick is its void shields. These power fields are strong enough to shrug off autocannon shells and even lascannon blasts, which turns the tank into a mobile bunker.
That protection is what made it useful against Titans. When a Legion needed to get troops across a battlefield dominated by god-machines, the Mastodon was one of the few things that could carry them through.
Crew, cargo and weapons
A single Mastodon can carry around 40 Marines, or swap that for up to two Dreadnoughts. The Salamanders’ numbers at Kharaatan back this up: about 150 vehicles for 6,000 troops works out at 40 per hull.
Its standard loadout is built for close assault: a forward siege melta array, a turret-mounted Skyreaper battery, two sponson heavy flamers and two sponson lascannons. It can also take up to four hunter-killer missiles.
- Around 40 Space Marines, or two Dreadnoughts
- Void shields that stop autocannon and lascannon fire
- Siege melta array, Skyreaper battery, heavy flamers, lascannons
- Optional hunter-killer missiles
- Used by Legions and the Imperial Army’s Old Hundred
Where you’ll see it in the lore
The Mastodon shows up in Horus Heresy material rather than 40k proper, since it’s a Great Crusade and Heresy-era vehicle. You’ll find it in the Forge World Legion rules and in novels like Vulkan Lives and The End and the Death.
It also appears in Legions Imperialis at Epic scale, so it’s still part of the modern Heresy range even though it doesn’t turn up in standard 40k games.
Key facts
- The Mastodon is a heavy assault transport used by the Space Marine Legions and the Imperial Army’s Old Hundred.
- It’s far larger than a Land Raider and was reserved for assaults on the most fortified positions.
- Void shields let it shrug off autocannon shells and lascannon blasts, and it was often used to shield troops from Titans.
- Standard armament: siege melta array, Skyreaper battery, two heavy flamers, two lascannons, plus optional hunter-killer missiles.
- It carries around 40 Marines, or up to two Dreadnoughts.
- Every Legion had some by the later Great Crusade, but they were always rare.
FAQ
Is the Mastodon a 40k unit or a Horus Heresy unit?
It’s a Horus Heresy and Great Crusade vehicle. It belongs to the Legiones Astartes of that era, not the modern 40k Space Marine range.
How many Marines can a Mastodon carry?
About 40, or two Dreadnoughts instead. The Salamanders’ deployment at Kharaatan suggests roughly 150 Mastodons for 6,000 Legionaries.
What makes the Mastodon different from a Land Raider?
It’s much bigger and carries void shields, which let it survive autocannon and lascannon fire. That’s what made it usable against Titans.