Saleh is actually a spawn of Yuris, born to fulfill his plan to engulf the world in negative emotions
They don't go much about his past, making Saleh seems like someone born evil, thus it's also probable that he's doing all those 'Power of hearts sucks and I will never be beaten by them' because he is a product of Yuris, who probably despise all those 'Power of Hearts'. Like Mao
being Olselg, son of Fenia, Saleh could probably be the spawn of Yuris, born to stir up the negative emotions amongst Huma and Gajuma and destruction, thus preparing for Yuris' arrival.
- This might be sound if it weren't for one scene where Saleh outright threatens two soldiers for spatting out racism. Sides, Saleh doesn't care if you're Huma or Gajuma. He'll try to step on your heart all the same.
- Of course Yuris didn't give shit with 'what race you are', thus that's moot point. Besides, Saleh wasn't really threatening to stop the racism, he likes it better if all lives get into chaos. If what I think is right, if Saleh was threatening the soldier to allow Agarte in Claire's body witness Zilva rallying the Gajuma to destroy all Huma, it's for the purpose that the soldiers would stop yapping and let him take Agarte, rather than showing disgust at the racist thoughts. And if we look at that, if that was Agarte in Claire's body and the guards were Gajuma, Saleh threatening them would instead BOOST the racism thoughts, because he's acting like "Oh, look at me, I'm a superior Huma" in front of the Gajuma soldiers.