Re: Looking for a new manga...
- 20th/21st Century Boys (Favorite manga of all time, one of the most amazing stories I've ever seen. Fantastic plot, amazing character development, and the mysteries just keep coming throughout)
- Liar Game (Not quite mystery or actionish but very, very psychological. Think of Death Note but less supernatural and much, much more intelligent. Akiyama is probably the smartest manga character I have ever come across)
- Monster (Same author as 20th CB. Pretty intense mystery story, very psychological themes and probably more action-packed than 20th CB is)
- One Outs (Same author as Liar Game. Revolves around baseball but it's more psychological than sports, the mind games are nearly on LG's level. Sadly the translation is pretty inconsistent so you won't be able to read it all, not to mention there are huge gaps in the chapters at times)
- Pandora Hearts (Action story but with a lot of mystery. The whole thing is filled with plot twists and crazy developments, some of the best mystery I've seen in a series like this and very much worth it)