We finally get it! The official website for Date A Live III began streaming the promo trailer for the upcoming third season of the series that introduces the Seventh Spirit Natsumi, voiced by Ayumi Mano. The song “I Swear” by ARMS is used for the opening theme.
Date A Live is adapted from the romantic sci-fi light novel series written by Kōshi Tachibana and illustrated by Tsunako. An anime adaptation by AIC Plus+ was broadcast on AT-X between April and June 2013. Date A Live II followed and ran from April to June 2014. Date A Live III is set to premiere January 11 on AT-X, TOKYO MX, and KBS Kyoto for a 12-episode run.
Source: Date A Live TV anime official website