UPDATE 2: Paraxade who has been going through the files of the game has uncovered audio from the Western version of the game which reveals that an explanation for Shadows out of character behaviour was included, but was cut from the final release.
One clip is of tails saying “Something’s wrong, he has some sort of chip on his head”
The second is of tails saying “You’re not yourself, you have some sort of device on your head”
So it looks like Shadow was to have a more obvious ‘mind controlled’ back story to him, but it got cut from the final version, yet in Sonic Toon they brought part of it back in.
UPDATE: More video and reports are coming in.
It turns out that at the very end of the game the is a sort of explanation. Shadow is not a robot. He had his mind controlled by Lyric. That’s why his voice sounds really strange. Some translation of his ingame dialogue has also come to light which suggests he says that “He will do anything to help Lyric.”
Whilst this would explain why Shadow is so out of character, it still creates plot hole in that there is nothing to show that this had actually happened since the western version of the game offers no explanation for his actions at all.
Original Story: Sonic Boom Rise of Lyric has been out for a while in the west. However in Japan the game is just released and there’s a rather noticeable difference… Shadow… is an android!
http://youtu.be/He4xWOVu1dw
Youtube user RaqibMarvelous uploaded a video showing the boss fight between Sonic & Shadow including the cut scenes which are done by the Japanese voice cast… and Shadow sounds nothing like he has done in previous games… he’s a robot.
Shadow has this mechanical like filter to all his dialogue like all the other robot characters making him sound more like an android. To compare, here is the Japanese version of Sonic Generations, Shadow pops up at 13:10 and you can hear the difference.
http://youtu.be/-dZs26bpwHg
There appears to be some dialogue changes too which don’t match up with the subtitles, if anyone can translate the dialogue for us we’d really appreciate it.