I just finished polishing off the side quests in The Fringes and there's a quest chain in Castrum Oriens that reveals that Gaius van Baelsar shut down an experimental project into chemical weapons as he saw the people of Eorzea as 'future subjects of the Empire to be ruled, not savages to be slaughtered.'
Which may have been brought up already, either here or elsewhere but I figured I'd bring it up regardless as I literally just finished it myself. Regula van Hydrus appeared to have a similar code of honour as shown by his willingness to accept the flawed nature of the technology binding The Warring Triad within Azyz Lla. Then there's the whole heroic sacrifice angle they took with him as well as him insisting that the Emperor may have need of the Warrior of Light in the future. Which, in hindsight, makes me wonder if that was a subtle hint at the future direction of the story given the ending of 4.0.