Originally Posted by Eye-of-God
I'll give you that in the flashbacks you don't get a since of him being unintelligent but you usually saw him fighting Madara and in battles we've seen people get serious no matter what their personality is. that being said when Oro revived him the first time it was insinuated in the last manga that his true personality was locked away.
Their personalities weren't locked away until orochimaru jabbed them with the kunai/talismans. The conversation they had before the fight was their true selves.