Skull Campaign

The Skull Campaign was a major armed conflict between the Lights of Purity, Skull Covenant and Tornusion Covenant. The war was very destructive, resulting in the deaths of hundreds of thousands, if not millions, of civilians and soldiers alike.

Opening Engagements (2555)
Following the Sentinel Crisis on Baphilas and the events of Halo: Dark of Night, the Skull Covenant, under Myluzeum the Hammer, attacked the Lights of Purity in a brutal campaign against their outer settlements.

Open War (2556)
The Lights of Purity began its first retaliatory strikes in early 2556, attacking multiple worlds under the control of the Skull Covenant, but ultimately failing. the Kig'yar Pirate Federation, which had declared support for the Skull Covenant in 2555, began to harass the Lights of Purity's logistical ships and would raid it's depots, seriously hindering it's logistics and leaving the outer settlements without key supplies or reinforcements for many months.

The Tornusion Covenant invaded the Skull Covenant, believing it could defeat them due to their ongoing war with the Lights of Purity, but was brutally beaten back and slaughtered by the Skull Covenant.

Turning Tide
Following the defeat of the Tornusion Covenant, the Skull Covenant renewed it's offensives into Lights of Purity space, attacking the settlement world of Sifess. Sangheili forces on the planet put up incredibly stiff resistance, eventually forcing the Skull Covenant to end it's attack on the surface and to begin orbital bombardment, marking the first major Skull Covenant defeat. By this point, Lights of Purity had defeated the majority of the Kig'yar Pirate Federation's raiding parties, and was now able to deploy more forces to the outer settlements safely. The Skull Covenant was unprepared to deal with the arrival of new forces, which culminated in their retreat, marking a turning point in the war.

Closing Months (2557)
Despite having turned the tide of the war slightly into their favour, the Lights of Purity were unable to successfully attack Skull Covenant space, and had received information that the Skull Covenant were amassing a gigantic fleet along with the Kig'yar Pirate Federation. In order to not give them the chance or ability to return the war to it's previous state, the Lights of Purity lead the Skull Covenant into a trap at the Battle of Dipholmis, otherwise known as Myluzeum's Last Stand. This battle resulted in the destruction of the majority of the Skull Covenant's fleet and the death of it's leadership, and also resulted in the complete dissolution of the Kig'yar Pirate Federation. Over the coming days, remaining Skull Covenant forces were engaged and defeated across Skull Covenant space until the dissolution of the Skull Covenant, and the end of the war.

Aftermath
In the immediate aftermath of the Skull Campaign, many worlds in both Lights of Purity and Skull Covenant space were left glassed, and hundreds of thousands of soldiers dead. Despite having suffered the brunt of the violence, the war strengthened the Lights of Purity, giving it's navy much-needed experience against unconventional Jiralhanae factions, and allowing it to expand into former Skull Covenant space. Following the war, the Lights of Purity became hostile to the Jiralhanae.