Aquila definitely traveled back through time. The reason why his personality changed by 180 degrees is probably because he's not his past self anymore. According to the time Uri got his hand injured, then Aquila probably arrived to the past some time after that or just right before the time Duke Orphe almost get killed. I think he was indeed once a "monster" the rumors told about him, but he changed after he met Lamia some time in the future? However, Lamia died due to unknown reasons (for now), so he decided to save her this time. Hmm.
Anyway, thank you for the translation! I highly appreciate your time and hard work! 😄