From artificially created summoning items made by Shirou _King_of_Fantasy_ and Lucas TheGodWithPassion were able to summon two antagonists of the universe as there summons.

BloodWinter Nexrotica

The Bearer of the Moon, also the protector of the Moon, BloodWinter was a warrior from a less recent time, she perished 300 years ago when she was overwhelmed by the Keter Armada, and stripped of her life.

When she saw that her entire kingdom of millions was wiped out by seven Keters, she lost all faith in her own abilities, and went without a fight.

She draws her power from the moon, and vice versa, when she died, the moon had lost all of its energy, and became nothing but a mass of matter in the sky...

BloodWinter had two brothers, Naga of the Sun, and Kitaro of the Reef. BloodWinter was the strongest of the three siblings, and would later go on to kill Kitaro.

BloodWinter is often worshiped by strange cults, and insomniacs, who see visions of her death, and her rebirth.

Though BloodWinter is the strongest of the three siblings, when she tried to fight The Core 1/3, or a being made up of life on Earth in general, she lost within ten minutes, and was spared.

BloodWinter is weakest during the day, and strongest at the Night, when there is a full moon, or a new moon.

Naga Deguro

Known as The Sun, he draws her power from the sun, and vice versa, though if he dies, the sun will keep on living, and resurrect him years later.

Naga manipulated BloodWinter into seeing that Kitaro was the enemy, and led to BloodWinter killing Kitaro, though Naga never has told BloodWinter the full truth.

Naga desires a partner, and will bond with his summoner, though a mutual connection, though he hopes for a much better, and more thorough understanding of his summoner.

Naga lost his will to live when he watched as the Keters killed BloodWinter, going into a dormant state of depression in the sun, untill, while he was asleep, found and killed by the Keters, though he doesn't blame the Keters.

Naga is strongest during the day, but even stronger in the evening when the sun is about to set and is at its most red point. Naga is much weaker during the night, and will usually hide in the sun.

.
.
.

If both of these summons are away from the sun or moon for to long, they will begin to feel a great pain. And if they go into a different dimension, they are weakened a lot, but, they can attach them selves to a different moon or sun.