Spinel is one of the most complicated characters of the lore. Spinel was originally created before the Hat Kid AMA server as a part of the Kamabo Lore Event.
Before the Story
Spinel was created either as a replacement or by accident. The true purpose for her creation is unknown. After being created, she wandered aimlessly, depressed and searching for a purpose. When she discovered the Crystal Gems were fighting, she thought she had found her purpose, and fought with them. Unfortunately, she ended up being cracked, lost and confused as a wanderer until she was Rejuvenated and ended up at Kamabo.
“Are you the light we seek?”-7705's first message. It was sent to Tartar during the Kamabo Event.
7705 was Spinel's original name (derived from Hover#7705). Due to the cracks and rejuvenation, a glitch occured such that he would be dragged into random universes against his will, leaving a portal behind. 7705 was dragged into the Kamabo Lore Event with Commander Tartar and Team Order in the first of these occurances. After the event was over, he started working to recover Tartar. Whether or not he succeeded is still unknown. He then spent many weeks asleep on Hat Kid's ship.
When 7705 finally woke up, he and most of the crew were captured by Delta Z. 7705 began after to turn pink, and after a while, attacked the crew at random. It was later revealed that there was a substance called Shadow, which he was composed of. Delta Z had managed to capture some of this essence. He had the ability to cover people in Shadow, and hover was covered in it for a while. It was shown to react to Hat Kid, eating away at her body. He slowly started to act more and more aggressive, until Peridot's ship showed up, which Spinel joined without a second thought.
After joining Peridot's ship, Peridot recognized her actions and behaviors similar to those of a Spinel. The Shadow decided to take on this name. Members of Melty attempted to report to Hat Kid that Kamabo was raiding their facility. Spinel intercepted this message, and went to see what was going on. Rather than stopping the raid, however, she began a hostile takeover using the current raid to help secure her victory. She then took over Melty from the founder, Mark Matte. She began having mysterious visions which she claimed felt like memories you've forgotten. After, she used the armies of the Gems, Kamabo, and Delta Z to play a game.
Spinel - Unrejuvenated
The cause of Spinel's disappearance was Spinel shattering. Hover and Kim went to the Crystal Gems to get Spinel fixed, with the knowledge from Spinel's "visions" arming them with the knowledge that she was a previous member during the Gem War. Spinel was able to be unshattered when all Shadow was called back to it's source. Spinel was able to return, better than ever, finally with the memories of her previous life. However, these memories caused her to be suddenly very depressed. Thanks to Hat Kid's kindness, however, she was able to return and because an advocate for peace and optimism. She feels like she owes a huge debt to Hat Kid, and would likely do anything she says.
In Generation 3, Spinel was Taken by Oryx.