Akari Tsukumo is a character in Yu-Gi-Oh! ZEXAL. She is the older sister of Yuma Tsukumo.
Her parents go on a lot of business trips, so she and her brother live with their grandmother Haru. Kari and her family don't let Yuma duel for some unknown reason, as demonstrated in the first opening which shows Yuma and Kari fighting over Yuma's deck (it is appears that Yuma is losing this fight).
According to the manga, Astral thinks it has something to do with the Emperor's Key. However, Haru seems to allow Yuma to Duel without Kari finding out. In Episode 16, she discovered that Yuma has been dueling despite her opposition, but apparently didn't mind and now allows him to duel.