bankai is a lot stronger and some bankais are also really big and some are small.
Im sure Shinigami can release their Shikai, since Ichigo released inside his sanctuary doing Getsga Tenshou against that Zanpaktou that had his Hollow form incapacitated. However its not known if they can release their Bankai. Zanpaktou are apart of the Shinigami, and their aim is to get stronger. Just before Renji released he was doubting his strength until he thought of someone to save. (Captain Byakuya). Apart of the Zanpaktou still lives inside the Shinigami. Bear in mind these are fillers, and Renji's Zanpaktou looks alot different, used to be a Baboon with a tail of a Snail.
Yes he is, and he claims that he killed his owner... ... muramasa is koga kuchiki's zanpaktou
No.
It is Engetsu
no.my mistake yes they are real just connect your sword with your spirit energy which is your soul and if you master your sword very well you will have zanpaktou
You need level 4 Soukatsui for Bankai, my sword is the best, its called bailing, epic bankai.
Shikai: Hyorinmaru Bankai: Daiguren Hyorinmaru
They are not declaring war... only muramasa wants war and he controlled the minds of all the zanpaktou (AGAINST THEIR WILL), and his reasons are still unclear...
Although some Shinigami posses different stages of bankai, there is no level higher than bankai.
Ukitake's Bankai hasn't been revealed yet, only his shikai has.
he does he says "shoot to kill, shinso" and it literally shoots to kill. i don't know if that is his bankai or if his bankai is when his sword turns to dust. The sword pieces have poison in them, so they kill the opponent...i dunno which one is the actual bankai, but i hope it helped :)
NO