In the 5D's anime, this "Immortal" could symbolize Carly Carmine in several ways:
In symbolism, one characterization of the hummingbird (what this "Immortal" resembles) is being a messenger. Although Carly primarily became a Dark Signer to avenge her defeat by the hands of Sayer, Carly prior to this has had "messages of the future" dictated to her in the form of her "Fortune Fairies" (as well as Misty's mind-reading) that all came true. Upon her "dark" transformation, she undertook this "messaging" role herself in foretelling Sayer's doom, which eventually comes to fruition when Sayer is defeated and sent to the Netherworld.
Another symbol of the hummingbird is love, joy and beauty, assets that Carly seems to embody due to her "naive good girl" complex, optimism and her "crush" on Jack Atlas before and after her Dark Signer ordeal.
The hummingbird also epitomizes on not trying to dwell on the past but to move forward; this is evident when Carly temporarily regains her conscience after her duel with Sayer and figuring out how she became a Dark Signer and why she damaged the Arcadia Movement's HQ building. Misty would then comfort her in telling her to forget what led Carly to become a Dark Signer and to ask herself why she is one in the first place as well as to move forward in figuring out what issue in Carly's life led her to the darkness.
In episode 39, Carly uses this card during her Ground Duel against Sayer. She Tribute Summons this card by Tributing "Fortune Lady Light" and "Fortune Lady Fire". The effect of "Future Visions" activates, banishing this card until Carly's next Standby Phase. This activates this card's final effect, destroying all of Sayer's monsters and inflicting 1600 damage to Sayer (800 for each monster destroyed this way), winning Carly the Duel. Right after his loss, Sayer was knocked out of the room he was in and down to the bottom of the building (in the dub, he went into the same shadowy portal that Carly was thrown in). The damage also caused the building to begin collapsing and because of that, Akiza Izinski and Misty Tredwell were forced to postpone their Duel. Afterwards, both this card and "Earthbound Immortal Ccarayhua" are recalled.
This card also appears in Carly's thoughts when she realizes she became a Dark Signer and did horrible things.
In episode 42, this card appears in a flashback shown by Rex Goodwin when he shows the Earthbound Immortals that attacked New Domino City last night. He also explains that they are the gods of the Dark Signers.
In episode 59, Carly uses this card during her Turbo Duel against Jack Atlas. She Tribute summons this card by Tributing "Fortune Lady Wind" and "Fortune Lady Water". This card then attacks directly via its own effect, but Jack activates the effect of "Battle Fader" to Special Summon it from his hand and end the Battle Phase. On the last turn of the Duel, Jack activates the first effect of "Majestic Red Dragon" to negate this card's effects and increase the ATK of "Majestic Red Dragon" by this card's ATK. Jack then tries to activate "Shockwave" in order to destroy his monster and inflict its ATK as damage to both players, but Carly activates "Earthbound Release" to Tribute this card and destroy "Majestic Red Dragon" as well as inflict damage to Jack equal to the ATK of "Majestic Red Dragon". The second effect of "Majestic Red Dragon" then activates, negating the effect of "Earthbound Release" and destroying it as well as inflicting damage to Carly equal to the ATK of "Majestic Red Dragon", winning Jack the Duel. With Carly's defeat, all the souls that were absorbed into this monster are released and revived.