'Wiraqocha' (Viracocha) is one of the most important Inca Deities. He was the god of the sun and the storms, and according to the folklore, the creator of the Inca civilization. Its importance was so big that even non-Incan cultures adored it. Its name literally means "Sea Foam".
This card's artwork is based on a condor, specifically the 'Andean Condor' which is one of the most sacred animals in the Inca Religion and one of the Peru's national animals, as well as Ecuador's national and most venerated animal.
This is the only "Earthbound Immortal" whose unique effect is different in real life than in the anime (its anime effect reduces the opponent's Life Points to 1 if you skip your Battle Phase).
In the anime, this card's effect is a reverse of "The Winged Dragon of Ra"'s, instead of reducing one's own Life Points to 1 to increase its ATK by the same amount, this card automatically reduces the opponent's Life Points to 1. Ironically, the downside to "Ra"'s effect is that it leaves the player vulnerable to even a low Direct attack (or Effect damage), while this card takes advantage of putting the opponent into that position with the general "Earthbound Immortal" effect of being able to attack the opponent directly.
This card can be both the weakest and strongest "Earthbound Immortal", before and after gaining its maximum ATK increase.
The same also applies in a way to the anime: despite having a very low ATK and DEF, it had by far the most powerful anime effect and was stated by multiple characters to be the strongest of the "Earthbound Immortals".
In the 5D's anime, this monster could represent Rex Goodwin in two ways:
"Rasca" is based on the Andean Condor, which is the largest flying land bird in the Western Hemisphere. This alone could be synonymous of Goodwin's enhanced physical physique when he reveals himself as a Dark Signer.
In Andean mythology, the Andean Condor is associated with the sun deity, and was believed to be the ruler of the upper world. The Andean Condor is also considered a symbol of power and health by many Andean cultures. This could represent Goodwin's "Inca" themed Deck as well as his desire to be the Supreme Immortal Ruler of the Crimson Dragon and the world.
"Rasca" is the only "Immortal" that appears to have a part of its body that neither pertains to its black bodily shape nor its corresponding rainbow color stripes. Around its neck is what looks like a wreath of white feathers which is often seen on real-life condors.
"Wiraqocha Rasca", in the anime, appears to be the largest "Earthbound Immortal" and has the largest geoglyphs.
This card's effect is the opposite of "Brionac, Dragon of the Ice Barrier". While the effect of "Brionac" lets you discard cards from your hand to return cards from the field to the owner's hand, this card's effect lets you return cards from the field to discard cards from the opponent's hand.
It is possible that Wiraqocha Rasca was intended to be Crow's Earthbound Immortal, as he was originally intended to be the main antagonist of the Dark Signers arc. This would fit into the theme of his deck utilizing "Blackwing" monsters, which focuses on a theme of birds, and Wiraqocha represents an Andean Condor.