Actually Sauron was a originally a very gifted craftsman of Aule, and step-brother to Saruman. However Morgoth later corrupted him with promises of power, teaching him of evil magic to dominate and rule over others; ultimately making him his lieutenant.
Sauron is known as such, but with a clarification, he is the second Dark Lord. He took over from Morgoth when he fell because Melkor was his teacher and mentor. The Valar were surrounded by a cohort of creatures also spiritual (but of lower rank) called maiar.
It begins after Sauron's master, the evil lord Morgoth, is defeated. Sauron may have gone into hiding, but he's still alive: the series will eventually show Sauron's creation of the titular rings of power—including the one ring to rule them all.
Origin. Sauron's original name was Mairon. He was the mightiest Maia of the Vala Aulë the Smith, and learned much from Aulë of smithing and handiwork, becoming a great craftsman and "mighty in the lore of" Aulë's people.
At some point prior to The Rings of Power, Sauron conjured a fresh physical form. He then seized the Southlands' crest from its last known king (who died 1000 years prior to the TV show's timeline) and assumed the identity "Halbrand."
The Lord of the Rings: The Rings of Power season 1 concluded shortly after Galadriel learned that Halbrand had actually been Sauron in disguise, but she didn't tell anyone.
As for whether Halbrand actually loved or romantically desired Galadriel is to be determined. Sauron is an expert manipulator and likely sees Galadriel and her power as an asset. In line with the old adage, "Keep your friends close; keep your enemies closer," he'd rather have her on his side than against him.
Morgoth is the more powerful of the two. Morgoth was the mightiest of the Valar, a group whose weakest member would outpace Sauron. However, there are some circumstances and eras in which Sauron would win the day. Morgoth was born far beyond Sauron but lost and surrendered much of his power.
Although Sauron's origins are angelic, he becomes captivated by the idea of ordering things as per his own will, which might be a possible reason behind him being lured by Morgoth, a Dark Lord who corrupted countless souls and waged wars against Elves and Men throughout the First Age.
Morgoth, the first to reign terror upon Middle-earth, was more powerful than Sauron and commanded an army of dragons and Balrogs. While both Morgoth and Sauron were cunning, Morgoth's rule and terror lasted longer and his corruption spread further, making him more formidable in the Lord of the Rings universe.
Bloodlines are very important in Tolkien's stories, and it makes a lot of sense that Sauron would fear the great-grandson of the man who cut off his hand. Aragorn carried the blood of Numenor with him. His genetic connection to the heroes of the Second Age established him as a dangerous opponent of Sauron.
Eventually, Morgoth was bound in chains by the Valar and thrown into the Void, leaving the permanent damage his evils had done, and his former lieutenant Sauron, to trouble the world. One day, according to a prophecy, Morgoth will rise again in great wrath, but he will be destroyed in the Dagor Dagorath.
Originally known as Melkor, Morgoth is essentially the Lucifer of Tolkien's story. Like the devil, Morgoth was one of the first children created by the God of Tolkien's world, but succumbed to jealousy and greed, especially over the creation of other races, and was duly disowned by his fellow Valar.
The Valar exile him permanently from the world, thrusting him through the Door of Night into the void, excluding him from Arda until the prophesied Dagor Dagorath, when he will meet his final destruction. His evil remains, however, and his will influences all living creatures.
Additionally, while he was in his weakened state, Galadriel could hold him off through the power of will alone. However, if Sauron had his One Ring and faced off in a battle against Galadriel, it's unlikely that there would be much she could do.
For that matter, the Valar didn't have the authority to remove another Ainur's power. If they had had that authority, they would have stripped Morgoth of his power, rather than going to war with him so many times.
Morgoth was taken to Aman and tried for his crimes. In the end, the Valar un-housed Morgoth by beheading him and "thrust him through the Door of Night", beyond the Walls of the World and into the Timeless Void. The Door is forever guarded by Eärendil.
Galadriel leaves Middle-earth in TA (Third Age) 3021 when she is around 8,000 years old. Given that the events of The Rings of Power take place before the Third Age, she's around 5,000 years old in the show. This is also corroborated by her birth date in Valinor of 1362 in the "Years of the Trees".
In an interview with Screen Rant, Vickers shared why he believes Sauron offered to make Galadriel (Morfydd Clark) his Queen in the Season 1 finale. "I think [Sauron] thinks that if [Galadriel] with him, he can affect his designs faster," Vickers said. "That's why he loved Morgoth.
For those that haven't read Tolkien's work, it's easy to see why many audiences suspect Gandalf and Galadriel are in love. After all, many of their interactions in The Hobbit trilogy practically scream romance. However, their relationship remains purely platonic in Tolkien's source material.
