The British Museum Case - 4

Miriam was silent for a while under her hood. At last she spoke.
"It is... complicated. She is called Shianna. Her past is.. mysterious."
Like you, I thought. This MIriam seemed to be intent on giving us the minimum of information. I don't like that. Okay, so I can withhold information with the best of them, but what gave Miss Spooky the right to expect our help without telling us what was going on?
"So why is she so dangerous?" I decided to ask the obvious question.
"Shianna possesses the Helm of the Morrigan. It is an artifact of tremendous power that was forged in Ireland more than two millennia ago.
"The Morrigan was an ancient Irish war-goddess of vast power. Legends abound concerning her, and I do not know what is true and what is accretion. This much I do know; that two thousand years ago Ireland was ruled by a race of sorcerers of such vast power that the common people thought them gods. These sorcerers took the land from its past rulers, giants of sorcerous power known as the Fomorians. The Morrigan was the queen of these sorcerers.
"Using their knowledge of sorcery, they extended their lifespans by centuries, so that they seemed immortal. But it is not for men to make themselves immortal, and as these spells weakened, so did they. They were unable to resist the invading Gaelic race, and they retreated to their underground strongholds. There they grew old and, one by one, they died. The Morrigan feared that dissolution, and so in a final desperate bid for life, she cast a spell that bound her soul to her golden battle-helm.
"But she miscalculated. The spell destroyed her mortal form, and she was helpless without a person to wear the Helm. For more than fifteen hundred years the Morrigan was trapped in this helpless state. None dared wear the Helm, and she could not communicate. Then, some years back, I came across the Helm in a private collection. My... abilities made me receptive to the Morrigan's power, and she used me to take the Helm and give it to Shianna, who is descended from the ancient kings of Ulster. I say the she used me because that is what she did. Having been a Queen whose magic abilities led men to worship her, she was not used to asking for help. It took a titanic struggle for Shianna to master the Helm and to keep the Morrigan from imposing her will upon this world. Understand, she is not evil, but she is from another age when such things were accepted.
"Shianna has been able to control the helm until now. For the artifact that we sought proved to be of the Fomorians. Reminded of that race, the Morrigan overpowered Shianna. I fear for what she will do now. I know that you find my story fantastic, but that I cannot help, it is the truth."