In the MOTHER 3 data he still is the masked man but, he removed his mask in the final battle if you watched the videos or played it in Japanese and used the online game guide it would make sense.

I played MOTHER 3 he went to fight a Robo Drago to avenge his Mother who died to protect him and his brother, Lucas. He lost the battle a Pigmask or Porky made him the masked man in the end Hinawa made The Masked Man be Claus but then Claus committed suicide when he took his last breath however...I never cried in MOTHER 3 only in MOTHER 2 when you collect all 8 melodies and go to a flash back with Ness walking slowly to his home then his Mother and Father talking the thing that got me was it was his memories which makes MOTHER 2 the Best out of the series for me. Also, Ness destroyed the dark side in magicant while Ninten and Lucas NEVER DID so then Ninten and Lucas are possibly not pure of heart, I mean sure Lucas pulled the Final Needle and then they went to a new world/heaven but, it destroyed the old one so Lucas has a bit evil side...(I didn't bother with the video since videos never start on youtube anymore...)

Your welcome but, also thank you your comment got me to level 10...