Note: This is an incomplete answer and is posted in hope that this helps someone figure out this riddle (as I am currently tunnel-visioned on Norse mythology even though there is a clue that literally states the opposite...)
Feel free to edit, add, or remove. I spent way too much time on this already :)
The answer may be one of the following:
The Norse Constellations (or zodiac signs), the planets in our solar system, or Heaven & Hell
Why Is The Reptile Opposed To The Shawl?
Constellations: The constellation Nidhogg is a serpent
Planets: Lucifer refers to the devil or the planet Venus when appearing as a morning star
Heaven & Hell: This possibly refers to Judas being a traitor or a snake. Other possibility is a version of the betrayal of Jesus where the motive for betrayed was not just for money, but instead the devil possessing Judas and offering him to betray Jesus. Some of the forms that the Devil takes is that of a serpent or dragon, both being reptiles. Jesus is from heaven; Devil lives in Hell. Jesus's robes look similar to a shawl.
Why Are Both Far From The Urban Sprawl?
Constellations: Far away from Earth
Planets: Far away from Earth
Heaven & Hell: Far from urban sprawl because you need to perish to enter either
One Gave Birth To Judah’s Master,
Heaven & Hell: The Devil is a fallen angel from heaven who again entered Judas (another name for Judah) therefore becoming his 'master' or Jesus came from Heaven (both a stretch)
The Other Calls Out To Avoid Disaster….
Heaven & Hell: Heaven is good and Hell is evil
Clue #1: The answer will come from Europe
Constellations: The Norsemen were originally from Scandinavia
Planets: Possible relation to origins of astronomy? (stretch)
Heaven & Hell: Heaven & Hell is a concept of Christianity which originated in Europe
Clue #2: They used to say the Vikings named one after a bird resting place
Constellations: Bit of a stretch but the Norsemen though the night sky was Yggdrasil where the rooster Víðópnir rested (except it goes back into mythology again...)
Heaven & Hell: The rooster Gullinkambi lives in Valhalla which can be related to Heaven (again mythology...)
Up & down
Constellations: You look up to see constellations but as the Earth rotates they will eventually be underneath the Earth (??)
Heaven & Hell: Trivial
Where it was always completely dark and full of light
Constellations: The night sky is dark but constellations are made of stars which are full of light
Planets: Space is dark (??)
Heaven & Hell: Heaven is full of light, hell is dark
Another possible answer may be
Days of the week