Although complex in design, the Grudge Vessel was very simple in concept. In short, the device was to replace the user's unpleasant feelings with pleasant ones. The device accomplished this by first embedding itself into the users brain. It then shut down and replaced the function of the users amygdalae and hippocampus. Once active, the device from then on analyzed the users brain activity. It pinpointed any emotions or feelings that were deemed by the device as negative and extracted them by (in short) converting them into electrical energy. It was then able to manipulate said electricity before re-converting and re-emitting it into the users mind as it's opposite "good" feeling -- essentially turning sadness into happiness, anger into forgiveness, hate into love, etc. The process in it's entirety about took place once every 0.47 seconds.