Each game takes place in a different region. Each region, respectively, contains its own “legendary” Pokemon. These are Pokemon which are extremely rare, so much so that only one is obtainable per game; Sometimes, only one is found per version, encouraging players to trade for high grade Pokemon that they cannot normally obtain.
The first legendary Pokemon are in Pokemon versions Red, Blue, and Yellow. This is a catalogue of the bird trio of Kanto region. All are powerful monsters worth seeking out.
Articuno, the Freeze Pokemon. At 5’07”, this is one giant bird. Its types are Ice and Flying, very helpful in battles as Flying type’s usual Ice type weakness is negated. Any Ice type moves do normal damage to Articuno.
Articuno’s name is a combination of “arctic” and “uno” (one), but its origins are actually Arabic. The Persian رخ or Rokh (more commonly known as a Roc) is a giant arctic bird of prey. It was said to be able to carry off an elephant, and shares many of the characteristics of the middle-Eastern Pheonix.
Articuno is available in all three Red, Blue and Yellow versions on the Seafoam Islands. It lies deep within an icy maze of caverns, far away from humans, and can be confronted only with the help of HM SURF and HM STRENGTH.
Zapdos, the Electric Pokemon. Only somewhat smaller than Articuno at 5’03”, this is still one large predator. Like Articuno, its type combination (Electric/Flying) helps to negate one of its weaknesses: Electric damage does not count as Super Effective against Zapdos.
Its name follows the trend of combining its element (zap) with the Spanish number for two (dos). It is based on a Native American legend of the thunderbird. The thunderbird was an enormous, sacred bird that could create thunder and lightning by flapping its wings. Some tales of the thunderbird are very also similar to the tales of the Persian Roc.
Zapdos can be found in the very last room or the abandoned Power Plant in all three versions of the games, presumably making its home in the most abundant source of electricity. HM SURF is required to gain access to the Power Plant. Zapdos will attack violently if disturbed.
Like the other two legendary birds, the Flame Pokemon Moltres’ name is a combination of its element (molten) and the Spanish word for three (tres). It is the last chronologically, and in-game it is also the last to be encountered.
The easiest origin to identify, Moltres is most likely based on the legendary Pheonix. The Pheonix was said to have a lifespan of 500-1000 years, and near the end of its life cycle, it would build a nest and set it aflame. It would then rise again from an egg in the middle of the ashes, reborn. Whether or not Moltres shares this ability is not mentioned, but it is certainly just as rare.
Moltres has gone through some dramatic physical changes over the years – Sometimes its wings are shown to be made entirely of flame, sometimes only partly. Its first appearance in the Kanto region shows its wings to be completely engulfed in (or possibly entirely composed of) flame.
Nearing the end of the game, Moltres can be found in an out of the way portion of Victory Road. As this is an optional route, it is possible to travel Victory Road and never find it. HM STRENGTH is required to traverse Victory Road, and thus to visit the legendary Moltres.