User blog comment:Abranon/Why didn't Regulus Black do more to contribute to Voldemort's Death?/@comment-306173-20120122130318/@comment-3475224-20120123165204

Kreacher maybe could have taken Regulus with him but he was ordered to leave by his master. He didn't have a choice. Regulus didn't know what the green potion would do -Dumbledore didn't- so he probably thought that it had no antidote, he didn't want kreacher to risk his life and the horcrux to save him when he may die anyway. Regulus probably knew how to fight inferi but could have forgotten (like Harry did) or not been able to perform the spell after he had been weakened by the potion. And how would Regulus have researched how to destroy a horcrux? He didn't want to ask anyone because it would endanger them and most people didn't know what a horcrux was. He did all he could.