Shingeki no Kyojin : Hearts of Paradise

Erwin Smith inherits the Colossal Titan instead of Armin. Everything after that is altered drastically. "Kenny told me something before he died. He said that 'everyone was a slave to something'. He had lived his whole life chasing that power. When he gave that serum to me, voluntarily, well... he stopped being a slave. He gave up his dream so that someone else could realize it."