Based on Aftermath Massacre I don't know if it's gonna be canon but we'll wait and see... So basically, Insanity came after hearing what happened and he was filled with shock and disbelief when he saw the massacre of Red Circle, Pea, Halo, Otto and Gravestone in which all of them are murdered brutally. Insanity: "No... He didn't deserve this... Why did you have to go out there Red...? Why did you have to go alone...? You knew this would happen... didn't you? Well... In that case Red... I won't let your death be in vain... Instead... I will kill him and make sure he pays for what he done! That goes for the other people he killed and suffer... I will avenge all of them... Then... I'll go on a rampage and kill more and more!~" With that... Insanity's determination to murder Decade for what he has done has increased his bloodlust. They knew Red was the only thing keeping him from going out of control. Without Red Circle, he would surely become unstable and go on a murderous rampage, innocent or not. If not checked, Insanity's lust for blood will increase and will continue to increase until he is killed the one who murdered Red and his close friends, gets killed, becomes unconscious, or if he is stopped (and maybe if he gets defeated that is...)
@Gallrio for Aftermath
