Generation IV of Pokémon introduced a variety of new creatures to the series. Fourteen Legendary and Mythical Pokémon debuted in the Sinnoh region, marking, at the time, the largest collection of new Legendaries and Mythicals introduced in one region. Although these two are officially distinct classifications, they function in very similar ways, power-wise.

RELATED: 10 Strongest Fossil Pokémon

As such, the Mythical classification should be included when evaluating the power of Sinnoh's rarest Pokémon and the stats, accessible moves, and abilities of Pokémon can all be found on SEREBII.NET. Some Legendaries and Mythicals from Sinnoh are mediocre when compared to the classification as a whole. Others, though, are among the strongest Pokémon in the game, even today.

Phione

Phione using an attack in the Pokémon anime.

Only obtainable by breeding a Manaphy, Phione was seemingly never intended to be a strong Pokémon. It has a very low base stat total, especially when compared to other Mythicals, and it can also only learn a small number of decent moves.

In a generation of exceptional Legendary and Mythical Pokémon, Phione is more of a gimmick than anything. It introduced the world to a new method of obtaining a Mythical, which although interesting, did not make it viable in battle.

Manaphy

Manaphy smiling and standing atop another Pokémon in the anime.

Manaphy is essentially a slightly better Phione. With the same typing of Water and the same ability of Hydration, the two are almost identical. There are a few slight differences, though. Manaphy's base stats each have the same value, which is also true of Phione, although each of Manaphy's stats is higher. Also, Manaphy has access to a small number of moves that Phione does not.

Manaphy can only be obtained from an egg that comes from Pokémon Ranger, making it another unique method of acquiring a Mythical.

Uxie

Uxie using an attack in the Pokémon anime

The Lake Guardians are, unfortunately, one of the least powerful Legendary trios in Pokémon, having relatively mediocre stats. But out of the three Lake Guardians, Uxie has the highest defensive stats, by a wide margin, although this is at the sacrifice of its offensive stats.

It can often withstand several strikes, allowing it to chip away at opponents' health. Uxie is weak to Bug, Dark, and Ghost moves, but as a pure Psychic-type, it does not have any extreme vulnerabilities. This helps its defensive capabilities greatly. Unfortunately, Uxie does not have access to many great moves, leaving it mostly as a defensive wall.

Azelf

Azelf using an attack in the Pokémon anime

While Uxie excels in defensive stats, Azelf does the same as an attacker. It has high Attack and Special Attack stats, as well as a high Speed stat. This makes it an excellent Glass Cannon with several powerful moves. It functions best as a Special attacker because most of the moves it has access to from leveling up are Special.

RELATED: 10 Pokémon With The Most Alternate Forms

However, it has unimpressive defenses, so if it does not handle opponents immediately, it can be in a great deal of trouble. If it can take out enemies quickly, though, it can be a capable fighter.

Mesprit

Mesprit smiling in the Pokémon anime

Mesprit is the most well-rounded of the Lake Guardians, having the same stat value for both Attack and Defense. While its Speed is the lowest of the three, it can both withstand hits and strike back against foes with great force.

Its accessible moves are lacking, with Mesprit only able to learn a few viable attacks via leveling up, but its relatively high Attack and Special Attack stats help to make up for its mediocre options.

Shaymin

Split image showing Shaymin's Land and Sky forms in the Pokémon anime.

When in its Land Forme, the Mythical Shaymin's stats are all equal. They are decent but not exceptional, making it difficult for this Pokémon to excel in any one department. It makes it a consistent pick, though, being able to take a fair bit of damage and use attacks with a good amount of speed.

When in its Sky Forme, though, Shaymin's stat spread changes dramatically. It gains much more speed and much higher Attack and Special Attack stats, lowering its defenses in the process. Both versions are useful, depending on the playstyle.

Darkrai

Darkrai uses Dark Void in the poster for its movie.

Previously obtainable through one of the best events in Pokémon, the Mythical Darkrai is also quite viable. Its best stats are its Special Attack and Speed. The rest of its stats are fairly high, but the Pokémon functions best as a fast Special attacker.

Darkrai truly shines with its ability, Bad Dreams, which reduces opponents' health if they are sleeping. Darkrai has a variety of sleep-related moves, letting it put enemies to sleep and damage them while they are incapacitated. This gimmick is extremely useful and makes Darkrai a capable combatant.

Heatran

Pokémon BDSP: How To Find (& Catch) Heatran

Relatively high defenses help Heatran to take attacks before going down, and its high Special Attack allows it to defeat many enemies in its way. The most significant downside to using Heatran is its extreme vulnerability to Ground-type attacks, which are often able to knock it out in one hit.

If these matchups are avoided, though, Heatran can be a devastating opponent. It also has access to several stellar attacks that help to increase this beast's viability.

Cresselia

Cresselia surrounded by white and pink light in the Pokémon anime

With rather high stat values in its HP and both categories of defenses, Cresselia is an exceptional tank. While its other stats are unimpressive, especially compared to other Legendary Pokémon, its stat spread is intended to allow it to be a solid wall against opponents.

RELATED: The 10 Weakest Pokémon That Don't Evolve

Even though it is not an offensive powerhouse, it has access to some great moves, many of which utilize its Psychic typing. It can gain a Same Type Attack Bonus from these, letting it benefit slightly from an attack boost.

Regigigas

Regigigas standing atop a hill in Pokémon.

Regigigas has an extremely high Attack stat, but it has one significant caveat. Its ability Slow Start halves both its Attack and Speed for five turns when it enters the battle. Regigigas has high defenses, which can help it withstand opponents long enough for this effect to wear off, but it can still be a nuisance to deal with.

Once the Pokémon gets going, though, it is monstrously powerful. Even though moves other than Normal do not get a Same Type Attack Bonus, Regigigas often does not need this boost.

Palkia

Palkia floating surrounded by pink light in the Pokémon anime

The mascot of Pokémon Pearl lives up to its importance in the game. Palkia sports an excellent dual-typing of Water/Dragon, allowing it to only be vulnerable to Dragon and, Generation VI onward, Fairy.

With an excellent Special Attack stat, Palkia can use the great Special moves to which it has access with devastating results. It also has good defensive stats, letting it stay in the battle longer and do more damage while it is there. An above-average Speed stat lets it often strike before opponents, perhaps taking them out before they can attack.

Dialga

Dialga floating surrounded by blue light in the Pokémon anime

The box art Legendary for Pokémon Diamond has one of the best defensive dual-typings in the series: Steel/Dragon. It is only vulnerable to Fighting and Ground, and it has a plethora of resistances. Dialga also has a stellar Special Attack stat and great moves with which to use it.

Similar to Palkia, Dialga has viable defensive stats, and with its excellent defensive typing, it can be incredibly difficult to take down, even though its Speed stat is not the most impressive in the game.

Giratina

Giratina floating surrounded by red light in the Pokémon anime.

Pokémon Platinum's main Legendary is incredibly important to the plot of the game, and Giratina's power shows exactly why. With the ability to change between its Altered Forme and Origin Forme, it can change its specialty easily. The Altered Forme focuses more on defenses, while the Origin Forme focuses on offensive stats.

It can utilize a variety of great moves and has an incredibly high HP stat. Giratina lives up to its fearsome appearance and is considered one of the best dual-type Ghost Pokémon.

Arceus

Arceus floatinf in a multicolored sky in the Pokémon anime

As the potential creator of the Pokémon universe, it is appropriate that Arceus is the strongest Mythical in its home region. Every one of its stats has the same value, which is also quite high. While it is a Normal-type, it can change its typing depending on which plate it holds.

Its signature move, Judgment, is extremely powerful and changes its typing based on Arceus's type, allowing it to utilize a Same Type Attack Bonus in every situation. Arceus is deservedly the most powerful Legendary or Mythical in Sinnoh.

NEXT: 7 Most Important Quality Of Life Changes In The Main Pokémon Games