CNR is a clone of Clark Kent and Lex Luthor that was designed to heal him following most of his body being burned and crushed in the destruction of the Fortress of Solitude (then called LX-15). Clark's DNA was used to stabilize the clone, so that after several months as Alexander Luthor, the clone developed Kryptonian abilities and became adopted into the Kent Family as Clark's "brother" Conner Kent. One day, he'll be Superboy.