Background
Even the royal families servants are not above Manannan's influence, and the maid that took young Gwydion proves it. She brought young Baby Alexander to Manannan at a dock near Daventry in hopes of being rewarded. Manannan turned her to ashes in payment. Later Alexander saw a strange dream allowing him to see how he had been kidnapped.
Behind the scenes
In the official continuity, Alexander was kidnapped by Manannan on shores of Lake Maylie (or in some accounts his nursery) without any accomplices. Annabel was the apparent personal maid for the twins. She was not evil, nor was she killed.
In KQ2 1/4 storyline, two strange henchman kidnapped Alexander.