Hamonah was once the Commander of the Blood Angels Legion's Crimson Paladin Order, until battle-injuries saw him interred within a Contemptor Dreadnought[1a], though he was still considered an honoury member[1b].
He took part in the Battle of Signus Prime, where the Primarch Sanguinius gave the order to advance upon the world's Cathedral of the Mark; which he believed was the likely base of the enemies that had attacked the Legion, since it entered the System. The Blood Angels' forces were then split into four formations, three of which would approach the Cathedral from three different directions. Hamonah was part of the formation led by the Archein Betric Sizal, which was composed of much of the Legion's artillery vehicles and Dreadnoughts, that was tasked with bombarding the Cathedral. However they would never reach it, as they were attacked by their allies of the Word Bearers's Unseen Hand Company, who unbeknownst to the Blood Angels were heretics that had betrayed the Imperium. Though the formation outnumbered the Word Bearers, the Blood Angels could not believe what had happened and their advance stalled, as a result[1a]. They then began to be driven back, when hordes of Daemons were unleashed on Signus Prime, which quickly joined the Word Bearers' attack. Now heavily outnumbered, Sizal was forced to order the formation to use their vehicles as barricades, to keep their foes at bay. This worked for a time, until a Daemon Prince appeared and bashed several vehicles out of the way, which allowed a group of Word Bearers to close with the Blood Angels. The traitors were then able to kill Sizal, which sent Hamonah into a rage and he unleashed his fury upon them. The Dreadnought's attack killed several of the Word Bearers, which caused them to retreat, but also drew the attention of the Daemon Prince which then charged Hamonah. As the Daemon neared him though, Hamonah let loose a point blank plasma shot, which destroyed the Prince at the cost of one of the Dreadnought's weapon arms. This attack however, caused the Daemons and Word Bearers to pull back and regroup, which gave the Blood Angels formation a chance to recover.[1b]
By then though Sizal's formation had been left devastated by their attacks, but another calamity had also struck the Legion. The Blood Angels had been enveloped by despair and madness, after their Primarch Sanguinius was severely wounded at the hands of the Bloodthirster Ka'Bandha, which caused many of the Legion to mindlessly attack their foes. This was true of Sizal's formation as well, but these maddened Blood Angels were easy prey for the Word Bearers and Daemons. These additional losses would have meant the end for the formation, when their foes attacked again, but their deliverance soon arrived. Chanting the Legion's Liturgy of the Blood, which somehow kept the Blood Angels' madness at bay, Archein Elai Jannus and his 202nd Company arrived and began a devastating attack against the Word Bearers and Daemons. Hamonah and the survivors of Archein Sizal's forces joined in on the attack, which completely destroyed their foes. Afterwards, Hamonah and the other survivors told Jannus of the Primarch's plan for the formation and the Archein agreed to continue Sizal's task of bringing the surviving artillery vehicles and Dreadnoughts, to bombard the Cathedral. He would succeed in doing so and the bombardment of the artillery and Dreadnoughts took a devastating toll on the Daemons near the Cathedral. This allowed the Blood Angels' main force, which had been driven mad by Sanguinius' fall, to storm the Cathedral and bring about the final stages of the battle. The bombardment though, caused the Daemons to repeatedly attack Hamonah and Jannus' forces, which fiercely fought to defend the artillery vehicles and Dreadnoughts[1b]. After the Blood Angels finally defeated their foes however, they discovered that aside from a heavily damaged Hamonah, the Daemons had killed Jannus and his forces[1c]. As the Blood Angels then later began to leave Signus Prime's System, the Legion honoured Jannus and the 202nd's sacrifice by creating a large memorial dedicated to them aboard the Red Tear. And Hamonah would lead the Legion's Dreadnoughts in standing vigil over it.[1d]