Marronnier Oukoku no Shichinin no Kishi

At the heart of a continent of eight kingdoms lies the Marronnier Kingdom. Its general, Baribara, has seven sons, each with a unique gift and serving as a knight commander. Bound by a single noble cause of heroically rescuing a princess someday, the brothers set out as goodwill ambassadors to the seven neighboring kingdoms. What encounters, trials, and destinies await them in these unknown lands?

(Source: Amazon Prime Video)