Pokemon 5th gen confirmed 100%

Just adding on on the legendary list:

Easy searching; CTRL + F and type the Pokémon you want to find after you toggled this spoiler.

 Spoiler

FIRST GENERATION:
Bird Trio;
-Articuno: Based on the legend of Rukh (Persian). This bird was also said to appear to people lost in the mountains. Refered to as the "Freeze Pokémon".
-Zapdos: Based on the legend of the thunderbird, the thunderbird was known for being the spirit of thunder, lightning, and rain in the form of a giant bird. The beating of the wings was said to create thunder. Refered to as the "Electric Pokémon".
-Moltres: Based on the legend of the Phoenix, just like Ho-oh, except that Moltres is based on Simurgh (A persian Phoenix.). Refered to as the "Flame Pokémon".
Mewtwo: Probably based on the idea of Frankenstein, as it is an attempt to create a better copy of an excisting Pokémon (Mew). Refered to as the "Genetic Pokémon".
Mew: It is purported by scientists to be the ancestor of all other Pokémon, it somewhat resembles an embryo. Refered to as the "New Species Pokémon".


SECOND GENERATION:
Dog trio;
-Raikou: A cross between a Smilodon and Raijū (From a Japanese myth). Refered to as the "Thunder Pokémon".
-Entei: Mostly based on the Chinese guardian lions. Refered to as the "Volcano Pokémon".
-Suicune: A cross between a few animals and the Fujin (A Japanese wind god.). Refered to as the "Aurora Pokémon".
Lugia: Luigia's based on Ryūjin, a Japanese god resembling the ocean. It's appearence is based on the stegosaurus and the plesiosaur. Refered to as the "Diving Pokémon".
Ho-oh: Just like Moltres, it's based on a Phoenix, Phoenixes have been said to rebirth from their own ashes. The immortal phoenix of China (Fènghuáng). Refered to as the "Rainbow Pokémon".
Celebi: There aren't many guesses where Celebi is based on, one of the theories is that it's just an union (Seeing as his heads resembles an union). Refered to as the "Time Travel Pokémon".


THIRD GENERATION:
Regi-trio: These are based on golems from Hebrew legends, "Regi" means "King" in Latin.
-Regirock: Refered to as the "Rock Peak Pokémon".
-Regice: Refered to as the "Iceberg Pokémon".
-Registeel: Refered to as the "Iron Pokémon".
Lati-duo: Both are probably either based on a cross between a jet plane and a dragon, or the philosophy of Yin/Yang and psychology of id/ego.
-Latias: Refered to as the "Eon Pokémon".
-Latios: Refered to as the "Eon Pokémon".
Kyorge: Based on the story of Leviathan, it most closely resembles an orca. Refered to as the "Sea Basin Pokémon".
Groudon: Based on the story of Behemoth, appearence is most likely based on the Ankylosauria. Refered to as the "Continent Pokémon".
Rayquaza: Based on the story behind Ziz, it's look is based on Chinese Dragons. Refered to as the "Sky High Pokémon".
Jirachi: Based on the concept of "Wishing upon a star", just like Celebi, there aren't things that are closely related to it. Refered to as the "Wish Pokémon".
Deoxys: Said to be from outer space, as well to be able to heal and adjust quickly. (Refering to his many formes.) Refered to as the "DNA Pokémon".


FOURTH GENERATION:
Emotion-Trio: Probably based on the Three Sacred Treasures of Japan. Uxie, Mespirit and Azelf would resemble Yata no Kagami, Magatma and Kusanagi respectively.
-Uxie: Refered to as the "Knowledge Pokémon".
-Mespirit: Refered to as the "Emotion Pokémon".
-Azelf: Refered to as the "Willpower Pokémon".
Dialga: Based on the Amphicoelias. Refered to as the "Temporal Pokémon".
Palkia: Probably based on the Plateosaurus. Refered to as the "Spatial Pokémon".
Giratina: Probably based on a basilisk. The closest legend is the one of Izanami. Refered to as the "Renegade Pokémon".
Cresselia: Probably based on space-objects, its rings look like the rings from planets and the two "ears" on his head look like half moons. Refered to as the "Lunar Pokémon".
Darkrai: Probably based on the Filipino "Manananggal", a monster who cuts his upper torso off at night to suck and eat human flesh and blood. Refered to as the "Pitch-Black Pokémon".
Manaphy: Might be based on Sea Angels. Refered to as the "Seafaring Pokémon".
-Phione: Phione is probably based on the same thing as Manaphy, Sea Angels. Refered to as the "Sea Drifter Pokémon".
Regigigas: Most likely based on the golems from Hebrew legends, "Regi" means "King" in Latin. Refered to as the "Colossal Pokémon".
Heatran: Heatran is most likely based on volcanic remains. Its Steel-typing references how the Earth's inner core is made of solid metal under immense pressure. Refered to as the "Lava Dome Pokémon".
Shaymin: Refered to as the "Gratitude Pokémon".
-Shaymin - Land forme: Most likely based on a cross between a Hedgedog and a Chia Pet.
-Shaymin - Sky forme: Most likely based on a cross between either a terrier-type of dog or a reindeer and a Chia Pet.
Arceus: Refered to as the "Alpha Pokémon".

 Spoiler

Arceus is particularly based on a creator deity, present in many world cultures. Or it may be a reference to the Chinese mythical creature, the Qilin. Its myth is nearly identical to that of the Pangu, the Chinese creation deity.

Arceus may also be inspired by (or a representation of) Avalokiteśvara who, in Buddhism, is either pictured with eleven heads and one thousand arms (the latter of which is mentioned in Arceus's flavor text) or in a white four-armed manifestation (which could look similar to Arceus's Normal form).

Some inspiration may have come from a horse, because of its Platinum sprite and attack movements in Pokémon Battle Revolution.

Arceus, as the master of the Dragon trio, may also based on Kaptan, the ruler of heaven and the king of the gods, according to the Philippine mythology.

Source: Bulbapedia - Origins and Pokémon types.
Typos might have been made, please do not flame me if I typed any Asian name wrong as I'm not from Asia myself.


As you can see there hasn't been any Pokémon with an entry like "God", "Devil" or "Demon" yet. Arceus was the Alpha Pokémon whilst Mew was the New Species Pokémon.

Deity and God go hand and hand. Look more at Arceus' information, it points to him being related to godly figures, including Avalokitesvara, who I've already referenced to. Arceus isn't a "god" in the sense of Christianity, but the back story we have on it would certainly point to it being godly in most cultures.

By the way, Giratina's back story doesn't seem to be included there, but I remember once it was stated that he was banished by Arceus to his own dimension. I have to find the original text. It didn't specifically say Arceus and Giratina, but it was very obvious it was referring to the two. Just as the lore behind the 3 pixies don't specify their name, and instead refers to the emotions they represent.

It was banished for its violence. It silently gazed upon the old world from the Distortion World.

Connecting that to the lore found in the game's library, adds more the the "Giratina is the 'demon' of Pokemon" idea.