Would the balrog use the ring?

Yes but, how powerful was Sauron really during the War of the Ring. He didnt have the power of the ring this time and he was missing a finger. He probably would have as much power as a balrog. Keep in mind that Gandalf won only because the Valar helped him.

What is the sea creature outside Moria?

The Watcher in the Water
The Watcher in the Water was a mysterious and horrific beast that lurked in a lake caused by the damming of the Sirannon river, beneath the western walls of Moria. The full shape of the creature is unknown; its visible parts were its tentacles, which were long, sinuous, pale-green, and luminous, with a fingered end.

Who defeated a Balrog?

Gandalf
Gandalf pursued the monster for eight days, until they climbed to the peak of Zirakzigil, where the Balrog was forced to turn and fight, its body erupting into new flame. Here they fought for two days and nights. In the end, the Balrog was defeated and cast down, breaking the mountainside where it fell “in ruin”.

What is the relationship between Sauron and the Balrog?

Both Sauron and the balrog are maiar and were corrupted by Morogth to serve him faithfully in the 1st age. After the War of Wrath Morgoth’s surviving servants scattered and went into hiding, this includes Sauron and the balrog of Moria.

What did Sauron do in the Misty Mountains?

As part of his preparations for his conquest of Middle-earth, Sauron began to people the Misty Mountains with Orcs, Goblins and Trolls. His creatures that had settled in Moria forged an uneasy alliance with the Balrog of Morgoth, though they greatly feared it and were easily scattered in its presence.

What happened to Sauron after the war of the ring?

Afterwords in the second age Sauron resurfaced and made a name for himself as the “Lord of the Rings” and he went around laying waste to the kingdoms of men and elves. He was defeated at the end of the age but came back in the 3rd age for the war of the ring, were he was defeated when his One ring was destroyed.