Voice Reference (5:42): https://www.youtube.com/watch?v=vQ9074Kl3iY

From the FE Awakening Wikia:

"When Henry was a child, his parents wanted nothing to do with him for unknown reasons, and had him sent to an elite magic school to get rid of him. The institution that he was sent to was a cruel place, where they carried out painful punishments, where Henry likely endured great hardships, as he ended up becoming slow to feel any pain. Henry almost always has a smile on his face, and is unusually cheerful. He has strong love for battles, dark magic and blood, which gives a jarring contrast to the cheerful personality he presents to others. Henry also cannot seem to comprehend the value of life completely, as in his supports with Robin, Henry did not know what was wrong with sacrificing innocents to win a war, as long as the final result is victory."

His smile and cheery appearance goes against his more darker personality. Despite that, he does care about the well-being of those around him (while having less care for others such as animals, enemies, etc). He has a Medium-High to Medium voice.