Many, many times, I've seen or heard "Mormons believe Jesus and Satan are brothers".

Technically, it's true. Mormons believe Jesus and Satan are sons of God, and by dictionary definition, people can extend this to say "brothers". (Jesus's is also God's son in the flesh as well as in the spirit, but nonetheless, the statement holds true.)

For example

* [One answer](https://christianity.stackexchange.com/a/24394/11102) to what is different about Jesus in the LDS faith is that Jesus and Satan are brothers.

* There is https://christianity.stackexchange.com/questions/5490, which boils down to "spirit brothers".

* And literally hundreds more instances as seen with a simple [Google search.](https://www.google.com/#q=mormons+believe+jesus+and+satan+are+brothers)

My surprise, I suppose, is that this is a surprise. I had thought other Christians believed the same thing, technically.

Possibly relevent scriptures:

God has sons (angels?)

> Where wast thou when I laid the foundations of the earth? declare, if thou hast understanding.

> Who hath laid the measures thereof, if thou knowest? or who hath stretched the line upon it?

> Whereupon are the foundations thereof fastened? or who laid the corner stone thereof;

> When the morning stars sang together, and all the sons of God shouted for joy?
 ([Job 38:4–7](https://www.biblegateway.com/passage/?search=job+38%3A4%E2%80%937&version=KJV) (KJV))

And Satan is a fallen angel... a (disowned) son of God?

> How art thou fallen from heaven, O Lucifer, son of the morning! ([Isaiah 14:12](https://www.biblegateway.com/passage/?search=Isaiah+14%3A12&version=KJV))

And Jesus is a son of god:

> I ascend unto my Father, and your Father; and to my God, and your God. ([John 20:17](https://www.biblegateway.com/passage/?search=John+20%3A17&version=KJV))

Does mainstream Protestantism believe that Jesus and the devil are "brothers"? If so, does the belief differ from Mormonism in any way? If not, what is the belief and how does it differ?