 In battle Magnus can let the sword attack his enemies on its own or use his own strength and control the sword himself.Either way, it is Magnus who loses energy ultimately, though this loss is delayed until he next grips or sheathes Jack.He bears a grudge against Frey, who 'abandoned' him, by giving him to Skirnir as a price for the latter bringing the former a Giantess with whom he fell in love; he summarises this by once admonishing Frey, saying 'blades before babes'.