As Eukari lies within the Elara's Veil, it is defended by the Emperor's Spears Chapter and a strike force led by Lord Trystance arrived to aid the world. However when the strike force arrived, Trystance discovered that the Aurora Chapter was already fighting the rebels and their commander berated the Spears for requiring others to fight their wars for them. This angered Trystance and he ordered the Spears' strike force to deploy right into the heart of the rebels' capital. Though they suffered heavy causalities, over three days of fighting, the Spears killed the rebels' Chaos Warlord and stole the glory of the battle for themselves. Afterwards Trystance informed the Aurora's commander that his Chapter had no right to mark Eukari as a victory on their war banners, since the Spears had done all the hard work to defeat the rebels. This led to a squabble between the two of them, but both decided to settle the matter with an honour duel between champions. However this led to more arguing, as both Chapters claimed they had won the duel. Eventually a shot rang out and both sides clashed in a battle, that saw their fleets sustain significant damage before a ceasefire was issued.
Since both Chapters are descended from the Primarch Guilliman, the Ultramarines Chapter sent a group of representatives to finally end the conflict. After reviewing the matter, the Ultramarines later ruled in the Aurora Chapter's favour and claimed the Spears had acted on rash impulsive instincts. Furthermore they claimed Spears' actions, did not follow the approved guidelines laid out in the Codex Astartes and the glory for the victory over the rebels, would be shared equally between the two Chapters. Though the Aurora Chapter was satisfied with the decision, Trystance was infuriated at the outcome, and vowed he would never set foot on Macragge again; even if the world itself was imperiled. The Emperor's Spears later bitterly claimed the outcome was decided by the Ultramarines' inflexibility and their favoritism to the more Codex-compliant Aurora Chapter and this led to the ending of their cordial relationships with the two Chapters.
- 1: Index Astartes - Emperor's Spears (Limited Edition), pgs. 13-14 - Footnote