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In 2535, Covenant weapons modified for human use were found in the hands of Insurrectionists on Charybdis IX. Hansen was sent to the planet to coordinate the tracking of the weapons, and attempting to remove them from the black markets and having them destroyed. She learned that Insurrectionist leader Jason Kincaide was getting his weapon shipments from a freighter, the Kestrel. With escalating riots in the planet's capital, Scyllion, Hansen had the frigate UNSC Midsummer Night come to Charybdis IX for support. After meeting with two members of its crew, Jacob Keyes and Akio Watanabe, she revealed that the ONI operatives on the planet had discovered a cargo container of modified Covenant weapons, meant for Kincaide. Hansen organized a meeting with Kincaide and two of his bodyguards, pretending to be a crew member of the Kestrel. However, due to nearby approaching rioters, she was forced to capture the three insurgents. Hansen, and the rest of the UNSC personnel in the city, attempted to leave Scyllion in a convoy of trailers and trucks. As they were escaping, RPG-wielding Insurrectionists disabled all of the vehicles, killing most of the ONI operatives. Kincaide escaped captivity and began to incite the mob.
Soon, Hansen, Keyes, and Watanabe were the only surviving UNSC personnel in the city. While the rioters searched for survivors, they engaged in small skirmishes against the rioters and retreated to a building. They rode an elevator to the roof of the building, barely evading Kincaide's modified plasma rifle bolts, where they called in for evac. However, their evacuation Pelican was shot down by Insurrectionists with RPGs. They then requested Orbital Drop Shock Trooper support, which was scheduled to arrive within twenty minutes. At that point, Keyes, Hansen, and Watanabe were extremely short on ammunition at this point, with all of them being limited to about one magazine each. Both sides began to only fire warning shots at each other and Kincaide started to arm the rioters with modified Covenant weapons. While attempting to listen to the rioters from above, Kincaide attacked the trio and killed Watanabe. Keyes retaliated by killing Kincaide. Shortly after, the ODSTs arrived and killed the remaining insurgents.
As the surviving UNSC personnel were evacuated off the planet, they were informed that Lieutenant Commander Dmitri Zheng detected a Covenant fleet arriving near Charybdis IX. While Keyes and Zheng were in favor of making a last stand alongside the three UNSC destroyers guarding the planet, Hansen revealed that she had a rank higher than both of them and ordered them to continue their search for the Kestrel. She ordered that they drop her off at an orbiting depot first, leaving her to certain doom at the hands of the Covenant fleet.
There is confusion over Hansen's rank. She was confirmed as a Captain, but whether she was part of the UNSC Navy or Marine Corps is unknown. On one hand, she had stated that she held a higher rank than Commander Zheng, which could mean she was Navy. On the other hand, she was very combat-capable for a Navy officer, and expressed surprise at Keyes' presence on Charybdis IX and viewed Navy personnel in a third-person view, which meant she could be a Marine. However, this would conflict with the first statement, as a Marine Captain holds a lower rank than a Navy Commander. It is possible Hansen had tactical command over the situation, similar to John-117 initially having authority over Lieutenant Haverson in Halo: First Strike.
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