400th Assault (Clan Steel Viper)
|400th Assault Cluster|
|Unit Profile (as of 3067)|
|Parent Formation||Alpha Galaxy|
The 400th Assault Cluster was formed specifically to provide Alpha Galaxy with an assault unit. They originally fielded King Crabs and Highlanders, and were later re-equipped with Crossbows and other assault OmniMechs.
On the 21st of November 3051, the 400th Assault Cluster landed on Benfled and defeated the defending Narhal's Raiders in four hours of pitched battle, costing the mercenaries two thirds of their forces. During breaks in the fighting, the 400th reconfigured their OmniMechs to confuse the Raiders' estimates of their capabilities.
After Tukayyid, the 400th absorbed most of the survivors of the 250th Assault Cluster.
In November 3052, the 400th invaded Blair Atholl together with the Fourth Viper Guards. The two Clusters decimated the Jade Falcons' Eighty-Ninth Striker Cluster and forced the remnants of the Ninety-fourth Striker to retreat off world.
The 400th Assault and the Fourth Guards paired up again in September 3053 to invade Graus in search of a rumored Star League cache. There, they again faced the Eighty-ninth Striker, as well as the Fourth Falcon Velites. Despite taking heavy casualties, the Steel Viper forces succeeded in conquering the planet.
Ejection from the Inner Sphere
In 3061 during the Clan Steel Viper assault on the Clan Jade Falcon Occupation Zone they were part of the fighting on Waldorff, which ended with the ejection of Clan Steel Viper from the Occupation Zone. By 3067 the cluster had moved to Homer.
The Crossbow OmniMech design featured highly in the Krait and Boa Stars in 3061.
400th Assault Cluster 
- Cluster Command Star (1 OmniMech Star)
- Trinary Alpha (3 OmniMech Stars)
- Trinary Bravo (3 OmniMech Stars)
- Trinary Charlie (3 OmniMech Stars)
- Trinary Delta (1 OmniMech/Elemental Nova, 2 Elemental Stars)
- Trinary Echo (3 OmniFighter Stars)
400th Assault Cluster - Veteran/Reliable 
- 5 Trinaries
400th Assault Cluster - Elite/Reliable 
- 95% full strength and fully equipped with OmnMechs
- Era Report: 3052, p. 59
- Objective Raids, p. 30
- Field Manual: Warden Clans, p. 165
- ”Falcon Rising”p.232
- Field Manual: Update, p. 79
- Field Manual: Warden Clans, p. 143
- Invading Clans, p. 94