Q: "If you got corrupted by a dark item (Black Shard), how would you look? how would you turn into that dark form, and what are your new abilities?"
That is what Anabelle would like like~ As for how she would turn into that, it would most likely be if her emotions gets the best of her, the poison magic would cloud her better thinking. New abilities: -Can disperse a thick poison fog. -Those 4 poison wisps are used to control the body of any being and morph them into a poison beast. - Can tap into her kingdoms poison (her people, even if she is nowhere near the kingdom) and use their bodies to create monsters , killing them in the process.
I would suppose if she was corrupted, she would act like how her mother was before she married. Attack first, ask questions later. Poison everything in sight to expand her kingdom, kill whatever being that stands in her way, and enjoy every minute of it.