Dr. Riddles has (or had) the Answer-Talker AbilityIn his first appearance, while claiming to "know everything" his eyes were identical to Duford and Kiyo.
King Bell used the King's Privilege to erase GorenGoren was only mentioned in passing during the Zophis Arc, being the source of turning well over half (probably around 70) of the hundred mamodo in the previous battle. He was also probably that game's Big Bad as Clear Note was to Zatch. Since they didn't have a way to bring back or restore the left over demons BEFORE the next battle (which Goren probably gloated about), King Bell used the privilege on at least him after he won the crown. Even if Baou Zakeruga does eat up his hatred, it would never excuse the pain and isolation those children faced.