Krynn's Vanguard had a hard-fought battle against Cornelia as she used the party's biggest weakness against them, targeting their mind rather than their bodies. She managed to incapacitate most of the party with a Psychic Scream spell and had them on the ropes before they finally broke through and took her down. She had taunted the party when they got into her sight "Oh my, what a charming guest. Let me take care of you...". As she fell, she lamented "So this is as far as I could get...All is in accordance with this carefully crafted script of ours...What a masterpiece! The ones that were being forced to dance around were in fact...us!" After she fell, her body transformed into the form of a slightly obese old man whose skin was as white as the scales on a newly hatched white wyrmling. There were streaks of black in his hair, and the eyes were also purely white with no iris or pupil. The eyes were only defined by black outlines on his face.
After declaring victory, Edelgard led the Imperial Army alongside the rest of the Black Eagles and Krynn's Vanguard as they entered the Plains of Solamnia on the road to Palanthus. At their camp, they were approached by Lord Arundel who told them that it might have been better to keep Cornelia around as an ally, and that he hoped "The Empire doesn't become another Relgoth" whatever that meant. The meaning was quickly figured out at Hubert came to report that Relgoth had been disintegrated by 'Pillars of Light' and that it was likely the work of what happened at Vash in the recent past, circa 250 A.C.
South of the old Alliance territory there is a valley where the earth is always aflame. Once, javelins of light fell from the sky there... They pierced the earth and set the forest ablaze, creating a land of torment. We believed it may have been the work of the goddess, Sothis, but... It was actually an attack by Those Who Slither In the Dark.
Those Who Slither In the Dark (TWSITD (pr. twisted)), are a nefarious group that has only been spoken about, but have not been encountered aside from the revealed form of Cornelia. Through some probing of Edelgard and Armantaro, it was revealed that the real Cornelia is more than likely dead as having 'two' Cornelia's alive could cause issues later down the line.
Armed with this new info, Edelgard asked Krynn's Vanguard if they'd be willing to snuff out TWSITD after they defeated The Immaculate One . They agreed and she thanked them. Now, it was time to rest and be ready to march on Palanthas in the coming days.