Kyoukaisenjou no Horizon, Guilty Crown Recommendations
Male main characters intended to be the "king", leading the good forces. Both Shu and Tori caused the death of a important girl in their past (Mana in Guilty Crown; Horizon for Kyoukaisenjou no Horizon). Also Inori from Guilty Crown strongly resembles Mana, while "P-01s" from Horizon strongly resembles Horizon Ariadust.
The two anime have events and scenes that aren't always fully understandable, with odd things. Kyoukaisenjou no Horizon is more funny, while Guilty Crown is more mature and serious.