Both Allen and the Earl are “mad puppets,” just like Mana?
Why did the Earl kill Mana & Nea’s mother right in front of Mana’s eyes? Why did the Earl leave Mana alive that day? Why, especially at the circus in LFOS, is the Earl so tuned into Mana’s (negative) feelings?
According to Hoshino (source):
I already decided on what the Millennium Earl’s human face would look like before the series started running. That’s why I’m happy that I finally got to show his face. I remember creating him after thinking that having a tired older man as the final boss would be interesting considering grief is one of d.gray-man’s themes.