User blog comment:Rjwstar/MGQ world`s various untold informations - Torotoro blog Q&A/@comment-26228098-20160115214727/@comment-26441687-20160118031209

Well it probably wouldn't work if you have it sheathed. The answer specifically says she was gripping it when she punched her.

And no, it's not as simple as just using dark energy to counteract holy energy, it doesn't work that way. There's apparently a reason why attacks worked during the original war but he has stated that he 'might touch upon that at a later date'. I guess there's a chance it's referred to in one of the future Paradox games.