Solar and Lunar

""You rise with the Moon. I rise with the Sun.""

- Zuko, Avatar: The Last Airbender

Due to its nature as an object that provides warmth and light, the sun has played symbolic and important roles throughout the history of fiction. Undead or demonic creatures have been depicted as being vulnerable to it, likely to its associations with light and fire. If associated with malevolence, can go in line with Light Is Not Good.

On the other end of the spectrum, the moon also has connotations of light, but it's been associated with The Undead and other supernatural creatures. Can also go in line with Light Is Not Good, although it can go with Dark Is Not Evil when dealing with characters like Friendly Neighborhood Vampires. Lycanthropes are depicted as having their transformations trigger when the moon is full.

The contrast between the two is a common motif. Compare Red Oni Blue Oni and Elemental Powers.

The sun and moon have also been personified by having both of them be a specific sex. For example, the pairing could be a masculine and harsh sun paired with a feminine and soft moon.

Anime and Manga

 * Solf J. Kimblee has alchemic circles on his hands that feature the sun and moon respectively. He happens to invoke Light Is Not Good.
 * Kannazuki no Miko: Chikane is associated with the moon, Himeko with the sun.
 * Neon Genesis Evangelion: Rei is frequently associated with the moon, initially as a visual motif, but later it turns out to be foreshadowing. Asuka is occasionally visually paired with the sun, but outside of suiting her Fiery Redhead personality the only real plot significance is to contrast her with Rei.
 * Seto no Hanayome: Sun and Lunar tend to be associated with the sun and the moon for obvious reasons. Sun is an honorable woman and kind to everyone she meets while Lunar has a bit of a rotten side and is Sun's Sitcom Arch Nemesis.
 * Cardcaptor Sakura has the eponymous cards each being of solar or lunar aspect, and ruled by either Cerberus (Kero) for the sun or Yue for the moon. Kero and Yue have strongly contrasting personalities and powers, befitting this split -- Kero is both figuratively and literally firey, and Yue can be cold and distant. Eriol's replacement familiars, Spinel Sun and Ruby Moon, have the same degree of contrast in their personalities, but running in the opposite direction. It's also lampshaded that Sakura's power is neither that of the sun nor the moon, "but your own mere power of the stars."
 * Heartcatch Precure has Itsuki and Yuri, Cure Sunshine and Cure Moonlight respectively. Especially telling as their personalities contrast one another (Itsuki's more friendly and outgoing while Yuri's more quiet and reserved). This continues on through to three other characters - Tsubomi (who, as Cure Blossom, contrasts Itsuki), Erika (who, as Cure Marine, is said to contrast Yuri) and the Dark Precure who is.

Comic Books

 * Moon Knight gets more powerful as the moon waxes and less powerful as it wanes. Under a full moon he's got the strength of 10 men but under a new moon he's only got his own strength.
 * Superman: Gains his powers from the yellow sun.
 * Superman Expy Apollo from The Authority is literally a solar battery, using up the energy that powers his abilities when not exposed to the sun, but recharging in direct sunlight.

Film

 * The Emperors New Groove soundtrack album: villain Yzma, in Snuff Out the Light praises the moon and calls on all things evil to extinguish the sun.
 * In Gremlins bright light will hurt Mogwai, and sunlight will kill them.
 * The sun is the official symbol of the kingdom in Disney's Tangled, a fact which plays heavily into making Rapunzel realize who she really is.

Literature

 * In The Silmarillion (the extended backstory for The Lord of the Rings) the sun and moon were fruits of the Trees of Valinor, Teleperion and Laurelin, that were put in hallowed lamps and carried across the skies by two maiar spirits (equivalent to lesser angels) as a warning to Melkor and a beacon of hope to the Children of Iluvatar. The stars were actually put in the sky before that (they are dew from Teleperion) and their placement marked the awakening of the Elves by the waters of Cuivienen. The first rising of the sun saw the arrival of Men in Beleriand. Traditionally, the sun is seen as female and the moon male since that's the gender of the forms the Maiar spirits that carry them clad themselves in. Evil things, like orcs and Nazgul, have no love for either sun nor moon but they will operate at night whereas only the strongest of dark things can walk freely during the day.
 * In Lloyd Alexander's Chronicles of Prydain, the sun and moon are emblems of two ancient royal houses. The emblem of the House of Don is the sun, on account of the fact that the Sons and Daughters of Don are descended from the Lady Don and her consort, Belin the Sun King. Meanwhile, the emblem of the House of Llyr is the crescent moon; this is on account of the fact that they are descended from Llyr Half-Speech the Sea King, and the tides of the sea are governed by the phases of the moon.

Mythology

 * Apollo of Greek Mythology is the god of (among other things) the sun, while his twin sister Artemis gets the moon.
 * Similarly, the original sun and moon deities of said mythology, Helios and Selene, were also brother and sister, and formed a trinity with dawn, Eos.
 * In Egyptian Mythology, the Sun was associated with many deities. Horus was a special case as it was claimed his eyes were both the Sun and the Moon, him being the personification of the sky.
 * Parodied in Terry Pratchett's Pyramids, where following the realisation of the myriad gods of Djelibeybi, the various sun gods all start fghting over the task.
 * In Japanese Mythology, Amaterasu is the goddess of the Sun, while her brother Tsukuyomi (who is rarely mentioned) is the god of the Moon. Amaterasu's Arch Enemy figure is her sort-of mother Izanami, who is an undead goddess who rules the underworld.

Tabletop RPG

 * Exalted. Namely, the Solar and Lunar varieties, though there are other types too.
 * Dungeons and Dragons Dragonlance setting. The phases of the three moons of Krynn affect the strength of magic corresponding to each moon's moral alignment (Solinari = Good, Lunitari = Neutral, Nuitari = Evil). The closer the moon is to full, the more powerful its magic.

Video Games

 * The Solrock and Lunatone from Pokémon, along with various other Pokemon who evolve according to the game's day/night mechanic.
 * Bayonetta's universe has the Lumen Sages representing the Sun and the Umbra Witches representing the Moon.
 * The Boktai series is big on this, though with a dash of Dark Is Not Evil applying to the lunar half of the trope.
 * One Dual Boss in Kirbys Adventure is Mr. Shine and Mr. Bright, an anthropomorphic sun and moon who alternate their attacks.
 * The sun/moon balance is the reasoning behind Tauren getting paladins in the most recent World of Warcraft expansion, Cataclysm. Their druids are trained by the Night Elves who worship the moon goddess Elune as their primary deity. In the Tauren's own cosmology the sun and moon are the eyes of the Earth Mother and they have adopted paladins with solar imagery (known as Sunwalkers) so that both aspects are represented.
 * Balance druids are gaining a mechanic where casting nature spells moves them closer to the moon and increases the damage they deal with arcane spells, while casting arcane spells moves them towards the sun and increases damage done with nature spells. The intention is that they maintain a balance between the sun and the moon.
 * A theme in Sengoku Basara 3, where Ieyasu represents The Sun while Mitsunari represents the moon. The final battle in Sekigahara is represented by a solar eclipse.
 * Nine times out of ten, if a Super Robot Wars installment has Daitarn 3, the robot that uses The Power of the Sun, then its moon-based counterpart, Zambot 3 is more than likely to be right beside it. Especially telling is when their ultimate combination attack, the Combination Crash, starts out with them using their finishers, respectively the Sun Attack and Moon Attack.

Western Animation

 * Avatar: The Last Airbender: Waterbenders and Firebenders draw strength from the moon and sun, respectively; a Waterbender's strength is greater when the moon is up, and at its absolute greatest when the moon is full, while a Firebender's strength is greater while the sun is up. Additionally, Waterbenders and Firebenders lose their bending during their respective eclipses.
 * My Little Pony Friendship Is Magic: Princess Celestia makes the sun rise and set, while her sister Princess Luna does the same for the moon. With Luna's Face Heel Turn and subsequent thousand-year imprisonment, Celestia took over the moon duties as well, but after Luna's redemption, she's ready to take the moon back. So Dark goes evil, but comes back.