Death Plunge and Death Leap

Death Plunge (イヅナおとし, Izuna Drop) and Death Leap (しんイヅナおとし, Shin Izuna Drop) are related Jupiter Psynergies featured throughout the Golden Sun series that are functionally identical but have different levels of power.

Basic Characteristics
Death Plunge and Death Leap are offensive, single-target Psynergies that are Attack-dependent, meaning characters with higher Attack ratings will deal more damage with these attacks. In addition, the caster's Jupiter Power and the target's Defense and Jupiter Resistance all factor into the damage dealt.

Death Plunge's visual effects feature the user launching themselves at the target, then jumping high into the air with the target. The user then forcefully slams the target into the ground, generating a small red shockwave from the point of impact.

Death Leap features the user grabbing the opponent, then jumping high into the air. The user then slams the opponent forcefully into the ground, causing a purple shockwave to emit from the point of impact.

Availability
Death Plunge and Death Leap are exclusive to the Ninja class series, which is available to Venus, Mars, and, to a lesser extent, Jupiter Adepts. Venus and Mars Adepts require both Jupiter Djinn and Djinn of their symbiotic element to access the class. Jupiter Adepts require large numbers of both Venus Djinn and Mars Djinn in a specific ratio of 6 to 3 to access the class.

Both Death Plunge and Death Leap are learned at level 12. However, only Death Plunge is available at first: Many Psynergies are only available to the more advanced versions of a class, and Death Leap is no exception. What separates Death Plunge and Death Leap from most Psynergies is that Death Leap replaces Death Plunge. To access Death Leap, the appropriate Adept must have at least 4 to 5 Jupiter Djinn and 4 / Djinn, making their class the Disciple or Master class. Jupiter Adepts are unable to access Death Plunge, due to the fact that they can only access the initial Ninja stage of the class but not any other stage.

It should be noted that the Disciple class (and thus Death Leap) is not available in Golden Sun, due to the player being limited to 7 Djinn on any one Adept.

Analysis
General:The Death Plunge/Death Leap duo are among the most useful Psynergies in the series for multiple reasons. First, each have excellent added damage for the stage they are learned at, higher than equivalent series like the Ragnarok and Odyssey. In addition, they have the useful ability to inflict Stun on an opponent, immobilizing the opponent for several turns. The Ninja has an excellent attack statistic to back up both Psynergies, and unlike other related series, the Ninja has a solid PP pool. This is in contrast to other classes like the Brute, where the Brute's low PP cap limits repeated castings of Planetary. For most endgame situations, Death Leap will be used interchangeably with Annihilation, allowing the Ninja to do excellent damage to any opponent.

By Game
Golden Sun: Should all possible Djinn be collected prior to Colosso, Isaac can enter the Ninja class for the tournament. Death Plunge's power and chance to Stun will make quick work of the other Colosso participants. Golden Sun: The Lost Age: The Ninja class will become available while exploring the Great Eastern Sea. Death Plunge is an excellent option for fighting the Serpent, due to the Serpent's Jupiter weakness, and could be used by both Felix and/or Jenna should the player so choose. Once the player can access the Disciple or Master stage, Death Plunge becomes an excellent offensive choice for anyone in those classes, but can be particularly useful against the final boss, which is Jupiter-weak.

Golden Sun: Dark Dawn: The Ninja class will become available during the latter portions of Morgal. Death Plunge is an excellent choice for combating both Sludge and the Mountain Roc. Death Leap is a good option for combating the final boss, as well as the Ancient Devil.

Trivia

 * Death Plunge and Death Leap are based on the fictional technique known as the "Izuna Drop" (with the Japanese names for the Psynergy series being directly named after the technique). The Izuna Drop is commonly associated with ninjas or similar characters in Japanese media, which reflects the two Psynergy being learned by the Ninja class series.
 * The English description for Death Leap in The Lost Age appears to contain a mistranslation - the description refers to the move involving hitting a foe with "a strange fan", but the Psynergy itself doesn't seem to involve a fan in any way. In Japanese, "ougi" could mean either "fan" (as in a handheld paper fan) or "secret technique" (as in a secret Ninja move or ability). It appears the translators misunderstood which term was intended, and thought the Psynergy involved using a fan to attack. This error is not preserved in Dark Dawn.