User blog comment:B214/Volume 21 info & spoilers/@comment-26865730-20160409182012/@comment-1359322-20160410012555

Tannin is ultimate-class but he never became a champion in RG, so no.

Devils have 3 ways to gain promotion.


 * 1) Getting contracts
 * 2) Rating Games
 * 3) Attaining actual war achievement

Number 1 is usually the way people get promotion.