technically madara wasn't exactly mizukage he controlled the fourth mizukage with a genjutsi and took control but to answer your question; no, now its Mei Terumī as fifth mizukage. and madara took advantage of nagato's (main source of pain) 'want of peace' and made nagato create akatsuki but now he is dead madara took over akatsuki as leader.
Madara never wasn't Mizukage or Akatsuki's leader.
Because how I understood in manga he were dead all the time.
When fourth war started, Kabutamaru resurrected Madara. And all were in shock.
Because in the period of all time everybody thought that the man in mask is Madara.
Madara Uchiha is the founder and true leader of the akatsuki, pein was leader on Madara's behalf receiving orders from him look at naruto episode ''disappearance'' you will see konan and pein meeting up with madara. and madara does tell pein to tell the other akatsuki members to hurry up with the remaining tailed beasts to capture., and yes yagura was the mizukage been under madara's control, making madara the true mizukage. yagura was just a ''vessel'' madara was using to fulfill his plan and he got kisame to join him as well, i hope i answer your question ^-^
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