Deviluke

Deviluke is referred to as being the center of the galaxy, though this is probably a reference to its importance rather than its placement in the universe. The planet of Deviluke literally rules the galaxy after the galactic unification wars led by King Gid Lucione Deviluke and as such, they hold dominion over all of the planets of the galaxy and its people.

Little is known about the planet itself other than its Gothic-esque culture, its containing many forests, really high mountains and its high level of technology. Much more is known about the citizens of Deviluke who are, at least, known to be many times stronger than Earthlings, and seem to have won their wars over the galaxy using just their own natural powers, which seem to have some sort of variety.

Appearance
Like their planet, the appearances of the Devilukeans follow a theme of devils and demons. All Devilukeans have tails at least half as long as their body length that end in a pointed tip of various shape. Most Devilukeans shown have had diamond-shaped tail tips; the Devilukean king, Gid, has a tail that ends in a trident-shaped tip (thought its metallic appearance and use as a blade during combat may hint that it's a weaponised replacement); the Devilukean princesses' tails all end with a spade shaped tip (whether this difference is due to gender or their Charmian heritage has not been revealed).

Other than their unique tails, Devilukeans, like with many other alien races, greatly resemble humans and are possibly a distant relative of them. They can easily be mistaken for being human; one example is when Maron was confused about how a human was talking to him, though it was actually Nana.

Their clothing follow the devil theme as well, but also appear to be inspired by playing cards. Emperor Gid's true form wears a black outfit that could be described as resembling a Gothic dark prince. Zastin is almost always seen wearing an archaic stone-like gray armor with many sharp edges, which might have appeared rather sinister were it not for its presence in a light-hearted manga series, and Zastin's own comically inept character. The princesses often wear black devil wings on their backs, which enable them to fly. Their clothing seem to be inspired by playing cards, mildly modeled after harlequin outfits with light frills, has a slight diamond motif, and striped stockings.

Lala's iconic "Peke" outfit is unique to herself. Besides the black wings, it does not seem to follow any kind of Devilukean trend, but rather is simply designed by Lala's goofy imagination, which is dominantly white, round and curvy, much like most of her other inventions.

Royal Family

 * King of Deviluke - Gid Lucione Deviluke
 * Queen of Deviluke - Sephie Michaela Deviluke
 * Princesses of Deviluke
 * First Princess - Lala Satalin Deviluke
 * Second Princess - Nana Astar Deviluke
 * Third Princess - Momo Belia Deviluke
 * Royal Palace Guards
 * Commander - Zastin
 * Assistants - Maul and Smutts

Powers and Abilities
All Devilukeans have superhuman strength. They are much stronger than Earthlings and most aliens of the galaxy. At one time, Lala even reached a stalemate against Yami, a well-known assassin, with just using her brute strength. However, Yami admits that living peacefully on Earth has weakened her. Another display of the Devilukeans' strength is when Gid was able to hit a tennis ball so hard that it caused Sasuga, the tennis club's adviser, to faint while standing.

Some Devilukeans have sort of blood lust emotion through fighting or when simply tempted by someone who gets them mad. Others like Momo have a lustful desire for sexual pleasure.

Gid and his daughters have shown the ability to shoot destructive beams of energy from their tails. The most powerful displays of this ability have been made by Gid, who used it to effortlessly destroy Nemesis' body, and Lala, who canceled out an attack from Darkness powerful enough to destroy a planet. However, so far, no other Devilukeans have shown this ability, so it is unknown whether or not it is exclusive to the royal Devilukeans. Nana and Momo's abilities to communicate with animals and plants are unique variations of the "charm" ability inherited from their mother, and no similar abilities have been revealed by any other Devilukeans.

Weaknesses
Despite the Devilukeans' "perfect warrior" abilities, they still have weaknesses. The overuse of their power can cause them to temporarily revert into their child-like forms, such as the case with Gid after the Galactic Unification Wars, and Lala during her fight against Yami in Darkness Chapter 44. The recuperation period can vary drastically depending on how much power was used: Lala returned to her normal form after a few weeks at most, whereas Gid remained a child for years.

Some Devilukeans are shown to have sensitive tails. When someone touches it, the Devilukean will lose power, but might manage to find enough strength to throw said person and let their tail go. The feeling of having their tail touched gives them an "erotic" sensation. However, this weakness is only shown between Lala and her sisters. It's also possible that this weakness is only limited to a certain few, as when Nana was asked if this applied to everyone, she mentions that everyone's different (Motto To Love-Ru Episode 11). As seen with Momo, Devilukeans with sensitive tails can pleasure themselves by rubbing it.

Trivia

 * In the anime, the way Devilukeans propose is by grabbing the females' breasts and confessing to her. Coincidentally Rito accidently did both without knowing it. Within the three days after the "said event", there is a cooling off period to cancel the engagement by touching the female's breast again.
 * The second names of the Devilukean Royal Family are reference to demons, while the only known Royal Consort's is reference to an angel.
 * Gid "Lucione" Deviluke - Lucione comes from Lucifer.
 * Lala "Satalin" Deviluke - Satalin comes from Satan.
 * Nana "Astar" Deviluke - Astar comes from Astaroth.
 * Momo "Belia/Beria" Deviluke - Belia comes from Belial, and Beria Berith.
 * Sephie "Michaela" Deviluke - Michaela comes from Michael.
 * There have been several information about Deviluke and the Devilukeans that resembles Planet Vegeta and the Saiyans from Dragon Ball. These resemblances appear to be intentional, as Kentaro Yabuki is known to be a fan of Dragon Ball.
 * The Devilukeans have superstrength, much like the Saiyans.
 * Devilukean women grow weak when their tails are touched, like the Saiyans.
 * The Devilukean king, Gid, was originally regular sized, but became small later on. The same thing happened to Goku in Dragon Ball GT. However, the reason why they became small is different.
 * In the first chapter of the manga (and the first episode of the anime), when Lala was showing Rito her tail, she commented "Even though I have a tail, that doesn't mean I transform when I see a full moon". This was an intentional reference to Dragon Ball, since Saiyans transform when they see full moons because of their tails.
 * Both planets conquered other planets. However, in the case of Planet Deviluke, the Devilukeans conquered planets in order to unite them during the galactic unification wars, while the Saiyans conquered other planets for bounty.
 * Both planets are notorious across the galaxy, and the other aliens are afraid of them.