I'm playing W2 and I would like to train 100lvl Magmortar, so I want to know where I can get Magmarizer and what is the best possible nature for Magmortar. Thanks in advance:)
Join Avenue (Antique Shop), Plasma Frigate B2
So you really just have to score at Join Avenue, or trade for a Pokemon holding one.
Source
Magmortar does have higher special attack, but physical moves are still usable. It gets moves like Earthquake and Cross Chop which are all very useful. So you could so for a Lonely, Mild, or Naive Nature. But I really do recommend going all special, with a Timid or Modest Nature.