@lemuel is no necesaraly true that he show no emotion, but in regard to reactions, he just doesn't have so much of it. For example when brauer confessed to him he was certainly happy but as he told if he wouldn't be a sage he would have been through the roof. He seems to go beyond emotions as mundane as they are because he has lived for so long and trained for so long. Apparently his master didn't wanted him to go by the very same route as he did, because he's much older and wiser to understand that power is not all attainable by oneself. I mean with the power he gathered he could rule them all but he's not, he loves his daughter, he seems to be grateful and loyal to his master and care for the one that loves him and his disciples.
But at the end if he's ordered to kill enemies he will without regret or compassion. Besides that they are indeed after his daughter, so I don't think he care the least about their lives or their circumstances. It's like cutting grass to him, they speak, they feel, they move but ultimately they are worth nothing.
That's why, he might not react but he's not like his master that abandoned something precious to him for more power until he didn't feel anything for anyone (indifference, not an unfeeling being, that would be scary). His master saw his own mistake and gave him a different path to travel.