Board Thread:Off Topic/@comment-24993958-20150615093256/@comment-26198742-20150615123047

He mostly uses them separately, He stopped using Nidhogg during his time at beacon(because of the third weapon form it used to have) and mainly used North, South and Raiden.

Niddhoggs weight wasn't a problem actually(Aidens Physical strength is on par with Yang(Higher when using his semblance) it was the third weapon form, the third weapon form as i said on the previous thread was causing glitches to the sword form and scythe form when transforming and using the weapons other functions(Such as the blade extending slightly in order for aiden to stab his opponents) so he left it untouched and then gave it too Derek who removed the gun form which eliminated any glitches it had previously caused by the third weapon form.

As for his Left arm that's a bit more tougher to explain but for an idea...

You know how in anime theirs always something wrong with a characters arm??