I don't think that tobirama is a villain. He is jsut very prejudice when it comes to the uchiha. All that has happened and he still holds a grudge toward them. War does that to people and i feel Tobirama has the best intentions gone wrong. He jsut wants to protect the village and he feels the uchiha will kill everyone. His mistakes led to more deaths in his village then he realized. But you have to look at the bigger picture too. Could the villages have been united if it wasn't for madara's moon eyes' plan?