Complex sentence: Beetle rescues Kubo while inconscient and obtains the Breastplate, but returning to the boat, they find that Monkey has been badly wounded in fighting and defeating Karasu and that their boat is destroy in the battle but restored by Kubo and Monkey's own magic.
Split into simpler sentences: Beetle rescues Kubo while inconscient and obtains the Breastplate, but returning to the boat, they find that Monkey has been badly wounded in fighting and defeating Karasu. Their boat has been badly damaged in the battle but restored by Kubo and Monkey's own magic.