Once Upon a Time season 5, episode 7, “Nimue,” explored the legend of the Dark One and how choosing power over love is actually a tale as old as time.

Nimue forged Excalibur. That fact remains true in Once Upon a Time season 5, episode 7, but not in the way the Arthurian legend tells its tale. Many intertwining mythologies made their debut last night as the Holy Grail, Merlin’s magic, Excalibur and the dagger’s creation, and even the first Dark One were revealed through a trip through time and realms. What does the forging of Excalibur have to do with the current predicament Emma and the heroes find themselves in? Well, it kind of started it.

So the legend goes…

Who gave Merlin his magic?

Stranded in the desert and dying of thirst, Merlin stumbles upon the Holy Grail. Asking for permission from the gods to drink from the chalice, they not only grant him permission, but gift him with the power of immortality and magic. A gift, that though helpful to many people, does come with a cost. After 500 years, and presumably many sorcerer’s apprentices, Merlin is ready to settle down with his love, Nimue. But the magic that keeps him alive prevents him from growing old with his chosen partner.

Forging Excalibur

That is, of course, until Merlin has a spark of genius. Forget all the magic in the world, if he takes the Holy Grail and forges a sword from the material he will be able to use the object that gave him the power to cut it out of him. For that to work, Merlin and Nimue travel to gain the first “spark” of life, the embers from Prometheus’s fire. Arthur melts the Grail using the fire and produces Excalibur.

The first Dark One

Nimue at first asked to drink from the Holy Grail in order to grow old with Merlin and live forever. But her request was not made from a position of love, but one of greed. In order to exact revenge on the man who burned down her entire village, Nimue wanted the power to end his life, a task that Merlin would not complete. For once a person of great magic takes a life, a darkness grows inside of them and the magic begins to take a turn.

As Arthur turns his attention away from Nimue, she drinks from the Holy Grail before he can forge the sword and in turn becomes endowed with the same immortality and magic. However, rather than choose a life of love and eternity with the man she loves, Nimue acts on her instinct to enact revenge and kills, thus beginning a line of darkness that currently manifests itself in Emma.

The creation of the dagger

Nimue, in an attempt to hold onto her power, breaks Excalibur in two and takes the spark from the fire to prevent Merlin from joining the two parts together. Rather than let the Dark One roam free in the world, Merlin enchants the tip of the sword to act as a bridle of the Dark One’s power. By attaching her name to the blade, a person can wield the power of the Dark One for better or worse.

Our modern day heroes

Emma and Merlin are off to find the spark that still exists from Prometheus’s’ fire, but in order to do that they must summon the Dark One who holds it hostage. Nimue exists in Emma’s head and luckily for Miss Swan, she recognizes that is true and does not give into the temptation to kill for more power. A bit of love, in this week’s case a necklace containing a special ring of Hook’s, is enough to ground Emma in the reality of her situation. If she kills Merlin she essentially kills the spark of Emma left burning inside of her.

As Emma successfully battles her demons in the forest and takes back the spark, the other heroes fail to get Excalibur from Arthur. Zelena, as it turns out, is still as horrid as ever. Not only does she lead the heroes right into Arthur’s court, she uses her magic to turn the fuller, or upper part of Excalibur, into a way to control Merlin. With his name on the upper half of the sword and Emma’s on the lower, who will win in the battle for control? Is this the way in which everyone failed Emma in Camelot?

Watch Once Upon a Time season 5, episode 8 AND episode 9, “Birth” and “The Bear King,” next Sunday, November 15 at 8:00 p.m. ET on ABC.

What do you think of ‘Once Upon a Time’s’ spin on Arthurian legend in season 5?