Hashirama will be betrayed by MADARA....
Hashirama will convince Madara by telling him to understand and give time to think on it.He will advice him to spare other uchihas from his selfish hatred and spare uchiha from fighting war.Then hashirama might try to win his trust by bonding all uchihas with senjus. So for sake of uchihas, Madara bond with senjus but will have hidden idea of project tsukoyomi as he love his brother a lot who give him his eyes to protect clan and to protect him.so to be with his brother, he made planned already but to achieve he need senju cells of hashirama. When other uchihas will not cooperate, he left village and found himself what are the secrets of achieving this plan.
So when he found the idea, he returned to village and willing to fight hashirama where actually, he just want to acquire his portion.He fooled hashirama in the end of fighting and slip away showing he is dead.Then after he awaken the rinnegan but have to die so transfer it to NAGATO and well planned with OBITO whom he converted like him by provoking.
There might be possibility that RIN herself want o die by kakashi's hand that time may be cause of her powers will bring chaos to village.
But the circumstances make OBITO changed.so as for MADARA who has no siblings want to create his world where he can be with his brothers.I will say, his idea was to brought love by casting tsukoyomi but by force by power not by LOVE and for his own self desire and wants which make him villain.
So what will be the conclusion from hashirama for sasuke is to understand the LOVE is important but it is not important to hurt others in the name of your LOVE.he might tell him that you are taking selfish decision just by thinking what was done to his brother rather than thinking what the shinobi is for village.shinobi doesnot think only for his family but also for all shinobi people like itachi and shisui.if itachi suffered pain so much so many other people too that does not mean taking revenge will satisfy you but making the things right by what they want you to understand to bring peace with LOVE.
These are just thought of me.i might be wrong.will see what comes in manga next. No one want to become bad.but circumstance and their care and love for others will lead them to choice between right and wrong.
(BTW: I am new here.)