List of characters by age

Ghosts
The ages displayed are the ages they would be if they were alive today.
 * Huizong Zhungxi: 96
 * Ichiro Tachimi: 92
 * Maria Tachimi: 36
 * Wei Zhenghan: 1,815
 * Meimei Shinozawa: 96
 * Jiao Shinozawa: 76
 * Reicheru the Yokai Spirit: 413-415 (depending on the media)
 * Ammon Ba: 4,712

Humans

 * Nicole Birou-Jennings: 24
 * Satoko Samo: 25
 * Toshio Samo: 6
 * Bridget Spotlow-Garbiel: 10
 * Catherine the Spellcaster: 26
 * King Kool: 14
 * Princess Starlight: 13
 * Gemma the Good Witch: 29
 * Kendra Knight: 14

Otters

 * Peanut Otter: 7
 * Baby Butter Otter: 2
 * Jelly Otter: rumored to be 5 or 6 (most likely the former)
 * Sophie the Otter: 14
 * Sydney Otter: 17
 * Opal Otter: 35
 * Ernest Otter: 35
 * Anna "Aunt Nanner" Otter: 37
 * Redolfo Otter: 40
 * Marilou the Otter: 14
 * Samuel the Otter: 14
 * CJ the Otter: 14
 * Luke the Otter: 15