Hi there I'm looking for a novel I read a while ago(how long I do not know it was January and all of a sudden it's April my sense of time has been murdered by studies). So the novel it is about a 'villainous' lady who in the prologue is destroying her way through the Royal capital to kill the royal family. Why? Because the prince engaged to her abandoned her, cheated on her and framed her on bullshit charges so she decided to wipe them out to save herself and her family and it's reputation (?). She is using firearms and other modern weapons (she's a military otaku apparently and made them with magic if this world) against the soldiers and guards and wiping them out before continuing to walk towards the palace. She uses her modern knowledge and magic to boost herself going as far as modifying her brain to resist against thoughts of murder hindering her. I am not sure where I read this either it is either a jp novel here on nu or something on rr is my guess.
The Villainess Will Crush Her Destruction End Through Modern Firepower I think this is what you are after