IVE JUST COME UP WITH THE BEST IDEA EVER!!! What if Artemis doesn’t have a shadow, but his hero form does? Because the black streak in his hair is his shadow, and when he transforms into his hero form the hair fades and his shadow comes back to give him more shadows to control. I imagine that Artemis’s ability to merge with Shadows would only be if he’s not using his hero form because then technically he’s ‘part shadow’ so can merge with them but he can’t use that in his hero form as he then has his shadow, and therefore is not ‘part shadow’.