Imprisoned by Love: The Bloodthirsty Prince Begs Me to Spare Him

Vampire + cold-blooded assassin The male lead takes her by force and loves her without hope of being loved in return. The second male lead turns dark later on. The female lead loves the second male lead from beginning to end. Contains bloodsucking, forced possession, and imprisonment. The ending will most likely be a bad ending, so proceed with caution if you can't handle angst.