In the Land of Leadale, Vol. 4 (manga)

Having finally reached the northern Kingdom of Helshper, Cayna’s first task is to deliver the letter she’s been entrusted with... to none other than her grandson, Caerick?! After a surprise meeting with her ever-expanding family, Cayna is off to seek out a new Guardian Tower: the Crescent Moon Castle. But a party of bandits—led by a foe unlike
any she’s faced so far—insists
on getting in her way...