Card Trivia:Firewall Dragon
- This monster is the Cover card for Code of the Duelist.
- This monster is the signature card of Yusaku Fujiki.
- As a Link Monster, it is the second signature card of a main protagonist since Yuma Tsukumo's "Number 39: Utopia" to not possess a Level.
- This monster is likely named after firewall, a network security system in computing that monitors and controls the incoming and outgoing network traffic based on predetermined security rules.
- Therefore, this card can represent Yusaku's actions as Playmaker against The Knights of Hanoi. Protecting the Virtual World against any threat that menaces it.
- This card is the first Link 4 monster to be released.
- This card has a downgraded form, the Link 2 "Proxy Dragon".
- This monster and "Decode Talker" are the first ace monsters of a spin-off protagonist whose Type is neither Dragon nor Warrior, thus breaking the pattern of the spin-off protagonists' ace monsters (though "Firewall Dragon" does resemble a Dragon and "Decode Talker" does resemble a Warrior, so they only break the pattern semantically).
- It is also the first time a protagonist uses a newly created Type (in this case, the Cyberse-Type).
- This card eventually replacing the 2300 ATK "Decode Talker" as Yusaku's ace monster mirrors both Jaden Yuki's "Elemental HERO Neos", who eventually replaced the 2100 ATK "Elemental HERO Flame Wingman", and Yusei Fudo's "Stardust Dragon", who eventually replaced the 2300 ATK "Junk Warrior".
