Madara being immortal with unlimited chakra means it's going to be next to impossible to beat him. Sealing techniques that have been used up to now all required the target to be immobilized, which can't really be done in this case. The only technique that could work is the RDS. It'd also be a very good plot move because both of its uses were important moments in the Naruto story, and this is a rather important moment.
In the hypothetical scenario where Madara IS sealed with the RDS, who do you think will use it?
In the hypothetical scenario where Madara IS sealed with the RDS, who do you think will use it?