i believe tobiis some part of madar, or just a fragment of his spirit. i mean, tobi has the same gloves and war fan as madara, heck, he hasnt even said he isnt madara despite everyone knowing that madara uchiha is on another battle field.
does that mean madara wants himself to be revived in tobiis body....coz thats the only part actually making sense...and tobii always thinks he is madara he must have been created for the sole purpose to revive into his body