RISING OF THE SHIELD HERO LN VOL 21

The Shield Hero Naofumi and his allies have been caught up in a strange phenomenon and sent flying back into the past, village and all. Naofumi enters into an uneasy alliance with Mamoru, the Shield Hero of the past, but Naofumi remains unable to completely trust him, suspicious of his actions. One night, one of the orphans under Mamoru's care comes to find Naofumi. The child proceeds to lead him to a chamber below Siltran Castle. Just what has Mamoru been gathering up these orphans for?