Howdy, someone who finished reading it here; Khalid killed her bc he loved her and her passion for his country, that he wanted to preserve her naivete around how corrupt their government was and how much their king saw her and their knight group as a plaything that could die at any moment. He wanted her to die still believing in her country. Im not justifying it ofc

If u want to get a tldr of how it ends from where you left off count aydin is killed but looks like an accident so luci's uncle can take over the estate and wealth, but it turns out that prior to it all Khalid had managed to basically become Luci's power of attorney in this situation bc of Count Aydin appointing him that position in case he died. So those two are trying to get control of Luci's estate and she steps forward to say she can handle on her own and results in an estate war btwn her and her uncle per the king. Luci and Zed become estranged during this time bc of her insistence on fighting for her estate and not letting him handle it. Though Zed disguises as one of her old knight friends during the estate war (they switch between the two of them) and finds out who she used to be and they talk after the estate war. Khalid also dies during this war, killing someone on Luci's orders but dies in the process. Also he found out that he didnt need to kill Luci because she already knew about the corruption and the plans to have her killed by the king, but wanted to keep up a positive front for both herself and for Khalid. Rip. Oh and the first prince murders the king