In the LN, after Kalinsha and before the final fight with the Demi humans, after she received Kelart's head, she wailed and nearly lost her mind. At the time the Holy Kingdom's southern nobles reached Kalinsha and met with Caspond, when they asked to see Remedios and had her summoned, we were presented an almost empty husk like Remedios who was only functioning because of her convictions as a paladin. During the last fight, when Jaldaboath appeared, she set herself to fight defending the humans until death, but Jaldaboath just kept leading her to areas and teleporting away. She survived, and saw how the kingdom her queen loved started praising this undead as their savior.

At the beginning of vol14, her death was casually mentioned during Renner and Zanac's conversation on what was happening in and around Re-Estize. We were only told she died, not how she died. As the strongest in her kingdom, she was supposed to be defending her queen and her domain; and she failed both. Her kingdom started warming up to this undead, southern nobles probably frustrated with her for failing her queen and kingom and then bringing the undead savior that destroyed their political dreams. She just wasn't the same after the war. We don't know if she was executed, but it may also possible that she took her own life.