G-Defend

From Storm in Heaven and one of their legacy groups, Bamboo Feathers:

Year 2022 A.D. At a time when anyone can travel around the world, there are more crimes occurring than ever. To protect the country from political terrorist attacks, a new Security System Garrison was created 8 years ago. To destroy this organization, terrorists have started aiming at the leaders of the Garrison, the Instructors.

Seven Instructors have already died in the line of duty, and to avoid another death, the 8th Instructor, Ishikawa Haruka, was given an assistant who would also act as his bodyguard. Iwase Motohisa, previously the Prime Minister's SP, falls in love at first sight with Ishikawa during a chance meeting, and then asks to be assigned as Ishikawa's assistant.