Madara stated on numerous occasion that he wanted Sasuke on his side due to his intellect and skill.
Madara tried to convince sasuke to join his side when he had EMS
Madara wish that Sasuke was born before obito because he will be a better suited follower (or get stuff done better)
The only option for Madara to get Sasuke on his side is to used the puppet seal jutsu to control influence Sasuke into the dark side.This will prevent Sasuke from defeating Madara or becomming a treat.
I believe kishi put in this puppet seal jutsu in to the manga to used it on Sasuke later down.Sasuke is protecting naruto without any complaint so far.There must be something to stimulate Sasuke vs Naruto battle.Probably during Madara dying moment,he will use this jutsu on Sasuke in order to carry on the cycle of hatred
Madara tried to convince sasuke to join his side when he had EMS
You must be registered for see images
Madara wish that Sasuke was born before obito because he will be a better suited follower (or get stuff done better)
You must be registered for see images
You must be registered for see images