Originally Posted by Masked_Felix

And aren't the "Sannin" just a shorter name of the "Legenery Sannin"?

Perphaps, as Zero said,
Junior Akatsuki
Akatsuki
Senior Akatsuki
Akatsuki Leader
Tobi
Maybe add "Student of the Sannin"

EDIT:
(1) Academy Student
(2) Rookie
(3) Genin
(4) Chuunin
(5) Academy Instructor
(6) Special Jounin
(7) Jounin
(8) ANBU
(9) Torture Specialist
(10) ANBU Squad Leader
(11) Hunter-nin
(12) ANBU Captian
(13)Student of a/the Sannin
(14) Missing-nin
(15) Elite Jounin
(16) Kekkai Genki Specialist
(17) S-Class Missing-Nin
(18) Akatsuki
(19) Akatsuki Leader
(20) Kage
(21)Ichibi
(22)Nibi
(23)Sanbi
(24)Yonbi
(25)Gobi
(26)Rokubi
(27)Nanabi
(28)Hachibi
(29)Kyuubi
(30) God of Shinobi