The conversation between human and AI assistant.
Since Voldemort never told anyone about his Horcruxes, how did Regulus Black discover his secret?
Interesting. I've always been curious about how Regulus figured it out. Do you know why he decided to destroy one of the Horcruxes?
Yes. Regulus realized the true cost of Voldemort's immortality and the destruction he had caused, and he was determined to stop him. He stole the Horcrux from Voldemort and replaced it with a fake one. He then removed the Horcrux from the location it was hidden, and had his house-elf take him to a lake where he ordered the elf to destroy it while he dived into the lake and perished.