Although his father died in the Osaka Natsu no Jin (Summer Siege of Osaka), Mamoru escaped from the castle with the help of his wet nurse when the Osaka-jo Castle fell, and he became a priest at Nanzen-ji Temple.
大坂夏の陣で父は戦死したが、守は大坂城落城の折、乳母の手により城を脱出し京都の南禅寺で出家する。