this
i beleive the last one summoned by KABUTO is the 4th hokage...i felt that wen i read the manga

*also i wonder how that ass kabuto got that massive chakra,i mean he summoned 6 people in the same time,ochi summoned 3 and was kinda halfway when he fought the 3rd
*the corpse on the grounds i beleive they are the sacrifice for the summons made by kabuto
*about obito being tobi,,i think its not an big issue
i mean yes the right eye,and the name,,but why would he be a bad ass and start making a war? or idk wat his last moments was sacrificial .