She is in the dark forest because she had kits with a cat from another clan. I'm sure that there are some other reasons as well. You can see after reading Crookedstar's Promise that she belongs there though.
Mapleshade went to the Dark Forest because of her dark deeds and her inability to let go of her grudges. She was consumed by bitterness and sought revenge against those who wronged her, leading her to be manipulated by the darkness within the forest.
Hawkfrost went to the Dark Forest because he was evil and tried to kill Firestar.
He was too curious and when he heard a whisper from the Dark Forest, he wandered into it and got lost.
She was jealous of Brairlight who got all the attention from their mother.
No, Crookedpaw was not trained by a Dark Forest warrior. He was mentored by Mapleshade, who was a former warrior of ThunderClan. Mapleshade was not a Dark Forest warrior but sought revenge on ThunderClan for her own reasons.
Mapleshade was killed when she was a full-grown warrior, so she was likely around 3-6 years old in human years.
longtail`s mom and dad are probably patchpelt and speckletail because pathpelt has black on him and speckletail has pale.longtail`s stripes came from speckletail`s tabby.
No.
ThistleClaw did go to the Dark Forest because TigerStar mentioned him in one of Erin Hunter's books to IvyPaw.
Mapleshade Records was created in 1989.
No, They cant.
Yes He walks there with Tigerstar.
No, he went to the Dark Forest.
In Warriors: Omen of the Stars #6: The Last Hope. Starclan is in danger because The Dark Forest is rising and planning to destroy Starclan. (I think I haven't read it yet but I know for sure that it's in that book)
Yes, Rainwhisker went to the Dark Forest in the "Warriors" book series after she died. She joined the ranks of the Dark Forest warriors due to her unresolved issues and thirst for revenge.
most likely starclan.