User blog comment:Miskos3/Fairy Tail Chapter 486: The Fourth Guest, Review/@comment-7418318-20160525151848/@comment-7418318-20160529065038

Sorry, but I just have to get this short comment out of my system. If you really don't want to talk about it anymore, just ignore it. There's no need for someone else to end the discussion for you. You can do it too.

So Gajeel can now choose to add functions to his lungs at will and/or change the fundamental functioning of his lungs?

Does that mean he can also modify his stomach to digest rocks and wood? Because that'd be pretty much on the same level (or maybe even below) as adding such a complex filtering system to his lungs.

Or can he now change his lungs to breathe under water? Because that would be exactly the same as filtering out MBP (from the lung's perspective anyway). Just filter the oxygen from the water without letting the water into the blood-stream.