Legiones Astartes: Siege Assault Battle Group

Release Date: January 10, 2026

Games Workshop continues its strong support of Warhammer: The Horus Heresy with the release of the Legiones Astartes: Siege Assault Battle Group, arriving on January 10, 2026. This boxed set is clearly designed to reinforce the grim, methodical warfare that defines the Age of Darkness, focusing on brutal close-quarters fighting, heavy armour, and relentless forward pressure.

Rather than serving as a simple starter box, the Siege Assault Battle Group feels like a purpose-built formation, ideal for players who want to lean into siege warfare, boarding actions, and grinding assaults against fortified positions.

What’s Included in the Box

The Siege Assault Battle Group contains 23 multipart plastic miniatures, all themed around breaching enemy defenses and holding ground under fire.

Cataphractii Terminators (12 models)

The backbone of the box is a pair of Cataphractii Terminator squads, each configured for a different battlefield role.

• One squad is armed with volkite chargers and power mauls, making them effective against infantry and ideal for clearing dense defensive positions.

• The second squad carries combi-bolters and power fists, providing a more traditional Terminator loadout with strong anti-armour and general-purpose assault capability.

Cataphractii armour is iconic within the Horus Heresy setting, trading speed for survivability. On the tabletop, these units are slow but extremely difficult to dislodge, perfectly suited to advancing through kill zones or anchoring key objectives.

Breacher Squad (10 models)

The inclusion of a full Breacher Squad in plastic is one of the most exciting elements of this release.

Equipped with boarding shields and boltguns and clad in Mk III power armour, Breachers are purpose-built for siege fighting. Their shields allow them to advance under fire, making them ideal for urban warfare, ship-to-ship combat, and defensive hold actions.

For many Horus Heresy players, Breachers have long been a thematic staple but were previously limited to resin kits. This plastic release significantly improves accessibility and hobby flexibility.

Leviathan Siege Dreadnought (1 model)

Rounding out the box is a Leviathan Siege Dreadnought, one of the most imposing battlefield units available to the Legiones Astartes.

Designed to demolish fortifications and annihilate elite infantry, the Leviathan provides heavy firepower and brutal close-combat threat. Its inclusion adds both visual impact and serious battlefield presence, ensuring the box does not rely solely on infantry.

Legion Transfers

The box also includes a transfer sheet with legion markings, allowing players to theme the force for a variety of Legiones Astartes, such as the Iron Warriors, Imperial Fists, Sons of Horus, Salamanders, and others.

Lore and Theme

From a narrative standpoint, the Siege Assault Battle Group fits perfectly into the Horus Heresy setting. The Age of Darkness is defined by prolonged campaigns, shattered cities, and grinding wars of attrition, and this box reflects that reality.

Breachers advance behind shields, Terminators absorb punishing fire, and the Leviathan smashes enemy strongpoints. This is not a fast, mobile strike force. It is a slow, inevitable hammer designed to break resistance through superior armour and relentless pressure.

For narrative and campaign players, the box offers a cohesive force that feels authentic to the lore rather than a random collection of units.

Gameplay and Tabletop Role

On the tabletop, this box provides a strong foundation for mid-scale Horus Heresy games.

• The Terminators act as durable assault units or objective holders.

• The Breachers provide resilient scoring units capable of surviving intense firefights.

• The Leviathan delivers heavy support and forces opponents to respond to a major threat.

The army composition encourages careful positioning, combined arms tactics, and steady advancement rather than aggressive alpha strikes. This makes it especially appealing to players who enjoy methodical, tactical games.

Value and Army Building Potential

While Games Workshop boxed sets often come with a premium price tag, the Siege Assault Battle Group offers solid value when compared to purchasing the contents individually. For players starting a Legiones Astartes force or expanding an existing one, this box can form the core of an army with minimal additional purchases.

It also pairs well with other Horus Heresy releases, such as Tactical Squads, Heavy Support Squads, or additional Dreadnoughts, allowing for easy expansion in multiple directions.

Hobby and Modeling Appeal

From a hobby perspective, this box is particularly strong.

• The Cataphractii Terminators feature heavy, layered armour with excellent surface detail for weathering and battle damage.

• The Breachers provide a rare opportunity to work with boarding shields and Mk III armour in plastic.

• The Leviathan Dreadnought offers a large, imposing centerpiece model with plenty of room for customisation.

Painters who enjoy grim, worn aesthetics will find this set especially rewarding.

Final Verdict

The Legiones Astartes: Siege Assault Battle Group is one of the most thematically focused and hobby-friendly Horus Heresy releases in recent years. It delivers strong battlefield utility, excellent modelling opportunities, and a clear narrative identity.

For Horus Heresy players who enjoy durable infantry, heavy armour, and siege warfare, this box is a compelling purchase and an excellent foundation for a Legion force.