This is Death Note. Possible one of the best mangas I've read. L, Near and Mello were my favorite characters. Light, Misa and Matsuda, I hate those three. What I really like is how the mangaka kept L alive in the form of Near and Mello. The three of them were arrogant, Near and Mello more explicitly, L not so much because he was also trying to cooperate with the NPA. Near was the passive part of L, Mello the aggressive. L was right in the middle of passive-aggressive. His passivity would restrain his aggressive side, and his aggressive side would be restrained by his passivity. Mello and Near didn't have the other side so no restrictions. Mello would act and Near would hypothesize. In the end, both of them defeated Kira. I would say that combined, they are better than L. And I think that if Mello hadn't act on the end, Near would've died and Mello would've caught Kira. In the end L would always win.
Anyway, great manga with great ending (Seeing Light desperately begging to Ryuuk gave me goosebumps).