Reiner Is A Selfless Person

Despite debuting as a villain, Reiner has always been selfless. He spent his childhood attempting to reunite his parents and much of his adolescence doing what he thought would save humanity. Reiner has risked his life time and again for the sake of his allies.

Moreover, he was even apologetic to Eren when encountering him again at Liberio. If Reiner had been born under different circumstances, he would have made for a charismatic hero.