RONIN WARRIORS GAIDEN

Things have calmed down considerably since the defeat of Talpa.​ Sage has gone off to America to study; Ryou is celebrating his birthday; Kento's won the lottery! However,​ the joyous mood disappears when the local news breaks a story about a strange killer in New York wearing mysterious armor.​ When the four warriors arrive to investigate,​ they are met by a new sinister force.​ The ancient sorcerer Shikaisen has discovered the power of the armors and is now intent on making them his own. (Source: Bandai Entertainment) — Description from AniList community (anilist.co).