Does Lev become a monster or a hero?

This is an opinion based question, and different readers are going to defend it differently.
Yes, Lev is a monster. He's been fooled into thinking that being a tithe makes him special, but after meeting Connor, Risa, and other unwinds, Lev comes to believe that unwinding is a horrible thing to do to a teenager. He so firmly believes this that he turns himself into a clapper. He believes that an act of terrorism that kills people will somehow improve the unwind situation. He's a monster for seeking out violence in order to somehow stop an impossible societal problem.
No, Lev is not a monster. Although he turns himself into a clapper, he doesn't go through with his plan. Instead, Lev saves Connor and never has the chance to finish the clapper plan. While that might not have been intentional, Lev's actions make him famous and he becomes known as the "clapper who didn't clap." Pastor Dan tells him that Lev's actions have gotten a lot of people talking about unwinding. Lev's actions might not have been intentionally heroic, but that doesn't change the fact that his actions had heroic results.