Xerneas, Yveltal, and Zygarde are based around Yggdrasil of Norse mythology. Xerneas is Eikþyrnir who lives under the life tree, Yveltal is Hraesvelgr who represents death, and Zygarde is the underground Nidhogg. Xerneas shares its life, Yveltal takes the lives of others to replenish its own, and Zygarde works to maintain the natural balance of the life-death cycle.
RESHIRAM, ZEKROM, AND KYUREM FROM GENERATION 5
Reshiram and Zekrom represent Truth vs Ideals, and the Tao philosophy of Yin/Yang. While Kyurem is the grey area in morality, a hollow shell left behind by the singular Dragon these three once used to be before humans tried using it for what they perceived to be “right”, when in reality it was just differing perspectives.
PALKIA, DIALGA, GIRATINA, AND ARCEUS FROM GENERATION 4
Dialga and Palkia are the Shinto legend inspired, godlike entities responsible for guarding and creating space and time. They come from a more scientific approach to how the universe works/was created, whereas Arceus and Giratina are more spiritual as they are designed with inspirations from various versions of “God” and “Satan” in dozens of different religions around the world.
GROUDON, KYOGRE, AND RAYQUAZA FROM GENERATION 3
Groudon, Kyogre, and Rayquaza are modelled after the biblical beasts; The Behemoth, Leviathan, and Ziz. Groudon created the land, Kyogre rules the seas, and Rayquaza guards the skies. Groudon and Kyogre helped shape the world (Alpha) and often nearly end the world in conflict with each other (Omega). Rayquaza acts as a neutralizing force to aid the world and its people.
HO-OH AND LUGIA FROM GENERATION 2
Ho-Oh has clear inspirations from various fire-birds in different legends from various cultures like the Phoenix, Fenghuang, and the Huma Bird, as it is associated with the power to revive itself and others from ashes, bring eternal happiness, and rainbow iconography. Lugia could be considered similar to the sea-dwelling dragon, Ryujin of Shinto myth, and he has subtle elements that seem similar to a beluga whale.
MOLTRES, ARTICUNO, AND ZAPDOS FROM GENERATION 1
Hot bird, cold bird, and zappy bird.
I love the first gen legendaries but this is true..