Regulus Black is preserved as an eighteen-year-old boy in the lake, but he is stuck underneath the water in stasis till someone wakes the inferi. Harry and Dumbledore manage just that, but Dumbledore forces Harry to leave the man behind. Even after Dumbledore's death, Harry doesn't get peace from the man haunting his dreams and thoughts and decides that he must return to the cave. This time, he won't let Voldemort himself stop him from doing so.