Kyou kara Maou! 3rd Series

Yuuri defeats Shinou at the end of season 2, but without Shinou's power, he and Murata can no longer access Shin Makoku. Yuuri, however, gains enough strength from the battle to return on his own. After his 16th birthday ceremony, he learns that much has changed in his absence. The ten noble officials had chosen Wolfram as the next Maoh, but Yuuri's return disrupts this decision. One noble objects to Yuuri reclaiming the throne, causing tension. Meanwhile, an ancient secret group emerges, threatening peace between humans and Mazoku. A struggle for legitimacy ensues, leaving the nobles uncertain about who truly holds the right to rule.