Dragons always tell the truth. They aren't incapable of lying; they see no point in it. Instead, they gain immense pleasure from presenting the truth in a way that allows the receiver to lie and deceive themselves. It is the nature of higher beings. They revel in their ability to control those they see as lesser beings. The case of what was to come for the three was no different.
Try as she might, Ria could not choose. Night after night, she shared beds with Em and Cú sharing in their love which ranged from intimate to desperate. Soon it was time for the next Singularity, and she found herself in another world flanked by two Alters. Surprisingly enough, neither one tried to kill the other. They were somewhat severe, dispatching enemies quickly and efficiently. When they entered the final room, which resembled a gothic throne room, Cú growled deeply as his tail thrashed. Of all the places to be, this was the last he ever hoped to be in.
Sensing a strange irritation poisoning his demeanor, Ria placed a hand on his chest. "Is everything okay?"
Before he could respond, a shrill female voice echoed through the room.
"Cú-chan, my love, did you miss me? I've waited so very long for your return." Though it was not immediately apparent where the voice came from, a girl with pink hair, about 5'2", appeared in front of Cú as she materialized before him, wrapping her arms around his waist and scowling at Ria.
"And who is this?"
Ignoring her question Cú kept his tone disinterested. "I owe you nothing, Medb. I am neither your love nor your toy. I am Life Bonded to Ria, whom I love beyond all reason. There was, nor ever will be, any room in my heart for you, you twisted, soulless, greedy bitch."
Pushing her forcefully away, Cú caused her to fall on her ass. Grinding her teeth, she stared at Ria before standing. "Is that so? Then let's see how strong that love is against my Greater Grail!"
Then she slit her wrist with a nail that appeared in her opposite hand, turning to let the blood flow onto the ground. When it hit, it pooled and then took the shape of various minions that stood ready to attack at her signal. With a dozen skeleton warriors now at her call, Medb looked at Ria and smiled before saying, "Now be mine." She then snapped her fingers, and a deep ringing could be heard, which caused Cú to place his hands over his ears. Frowning, Medb snapped again, causing the ring to grow in intensity and Cú to begin panting heavily as he bent over, clutching his ears in evident pain. Snapping them again, intensifying the call a third time, Cú was on his knees, moaning and panting in pain.
"Last time I'm going to ask Cú-chan." She snaps a final time, and the ring becomes almost too loud. Cú's back arches, and he screams a few seconds before his arms drop to his sides, and Ria can see blood from his ears on his palms.
Watching in mortified horror, Cú's head slowly turns to lock on Ria, forcing her to watch as the sadness in his eyes fades and is replaced with sadistic lust. The same passion she saw in her nightmare version of Alter. At that moment, her mind knows he is gone, but her heart refuses to let go, and her insides scream.
"Now, my pets. Shall we play with our new toys?"
"Em, I need you to take the skeletons; I'll deal with Cú."
"What are you fucking crazy! You don't stand a chance!"
"Just do it, Em!"
Medb laughs. "It'll be fun watching Cú eat you alive in the least sexual way possible. Such a fitting end for trash. If he truly loved you, he never would have succumbed."
That stung more than Ria cared to admit. Especially given Cú's and her conversation not that long ago. Glancing down at her ring finger, she sees the faint outlines of the rune ring he gave her. Watching the blue light shimmer from some inner light, Ria knew he was there somewhere and was suffering. Steeling her resolve, she knew she couldn't let things stand. He didn't deserve that, no matter what had happened. For a few moments, Ria watched as Alter rose and materialized his lance. Grateful he might be starting with his Phantasm, Ria found comfort in the thought she might stand a chance.
Not bothering to call her staff, she materialized her claws and quickly coated them with dragons' bane. It takes a dragon to kill a dragon, a play on words she always came across searching for the stone, and they were words she chose to live by when faced with the strongest challenges. Now observing Alter, noticing his movements were laggy and his breathing heavy, Ria smiled slightly, knowing somewhere in there, Cú was fighting for his life and hers.
"What are you waiting for, Cú-chan KILL HER!" Medb screamed, and Cú growled as he made a halfhearted charge into Ria's clawed defense.
"That's it! Slice her in half! Make her bleed!" Medb croons.
Darting back before lashing out with his tail, Cú forces Ria to jump and duck so his following swipe at her head doesn't decapitate her. Noticing each subsequent movement remains slow and lazy but seems to be gaining strength and speed, Ria quickly glanced down at Cú's Command Seal and saw it was growing fainter and fainter, meaning she didn't have much time left to save him.
"Mo grá, I can't hold out much longer. Please, you know what needs to be done."
Looking through the eyes of a beast and into the eyes of her beloved, tears begin to fall from Ria's eyes. "No. There has to be a way. I still have time."
Alter swiped with his claws in rapid succession, forcing Ria to go on the defensive a few moments before she could duck under his swing and dart around behind him making sure to stay out of his tail reach.
"No. There is no more time. If you wait much longer, I will lose myself entirely. Please, while I can still love you and not feel regret."
Turning to look at Em, who has dispatched the last of the skeletons, Ria notices the look of shock on his face, which she cannot fathom until Alter then turns and growls as he readied his Noble Phantasm Gae Bolg.
Has it come to this? If so, I only have one shot. "I will always love you, Cú. Until the stars fall from the sky."
"And I you."
Then the tears fall as Alter charges his Phantasm, and the last light begins to fade from her seal. Time seems to slow as Alter releases his spear and the previous words escape his lips as Ria holds up her fist and exclaims, "For the bond we share, with this Seal, I command you, Cú Chulainn kill yourself!"
Time speeds back up, and his spear shoots toward her heart. Still, at the last second, when the command is sent, it changes course. It returns to pierce Cú in the gut, causing a primal roar that can be heard above the ring of the grail as Medb screams in protest, but only long enough to provide a distraction that allows Em to sneak behind her and slit her throat as Assassin. With Medb dead and Cú dying, Ria walks over to his body as the charm effect begins to disappear.
"I had wanted to stay with you forever." He gave a sharp pained laugh.
Reaching out, Ria touched his face, but he took her hand and kissed her ring finger, causing the runes to light one final time before they faded entirely.
"Em, you asshole, where are you?" Cú's breathing becomes more labored as Em walks up. "Promise me you will take care of everything. It will take a man like you to ensure everything works out. She needs you way more than me."
"I knew that already, you idiot."
Taken aback by their sudden affection Ria is rendered speechless.
"Now let me die, Ria. Em..." Cú reaches out his hand towards Em, who takes it, allowing Cú to guide it to his spear. "Take it. Use it to protect her until it's someone else's turn." Then he looks at Ria lovingly.
"Goodbye, Mo grá. Until the stars fall from the heavens." Then with his hand on Emiya's, which is still on his spear, Cú jerks out the tip and gasps in pain as the light dies from his eyes and the blood drips from his spear; the last of Cú life spilling to the earth of a world not their own.
Within seconds his body begins to disappear, and Ria quickly bends down to take his earrings, removing hers and discarding them on the lifeless stone ground as she replaces them with his. With his body gone, all that is left is a small black stone. Picking it up and walking towards Em, her voice is emotionless and dead.
"Let me see the spear."
Emiya holds the tip up, and Ria places the stone on the most extended tang before calling forth a strong enough fire to soften the metal enough that the stone can be secured.
"His philosopher stone. I am not sure if you can access it, but it belongs with what is left of him."
Emiya nods but says nothing as she turns without another word and leaves the Singularity unable to deal with anything, including the immense loss that now plagues her heart and soul.