- "Celtic Guardian" has a retrained counterpart, "Obnoxious Celtic Guard".
- This card appears in the artwork of "Triggered Summon" and "Summoning Clock".
- The Bandai version of this card has 1300 ATK, 2200 DEF and 5 stars, the Konami version has 1400 ATK, 1200 DEF and 4 stars.
- In Ireland, "Celtic" means protector so this card's name in Ireland would translate into "Protector Guardian"
- There is a card that has been debated as to being this card's counterpart, "Obnoxious Celtic Guard", being that it is specifically "Guard" and not "Guardian"; at the same time, the main reason for the change was so it would not be counted towards the Guardian Archetype.
- This card bears a strong resemblance to Link, a character who appears in various Zelda titles created by Nintendo and also appears in the Philips CD-i Games for the CD-i Console: Link: The Faces of Evil and Zelda: Wand of Gamelon.