[Boom Universe] When Shadow learns that Knuckles has a crush on him, he decides to use that to find Team Sonic's weaknesses. What happens when Shadow starts to like how Knuckles treats him? [Knuxadow]

Sonic spotted Shadow outside of the village one day. Curious, he decided to follow him to see what is up with the dark hedgehog. After finding out the reason why Shadow likes being alone in that one particular cave, he decided to stick around and company him. It makes Sonic realize that Shadow isn't really that evil and it also makes him grow closer to the dark hedgehog. SFW book.

Sonic and his friends found an ancient black heart gem from the tomb chamber. They just thought it was an ancient artifact but when Sonic touches it, an unknown black entity enters his body. Sonic goes through different changes for days, the unknown entity takes control of his heart and his body.