Eiha is generally classified as a skill that inflicts light Dark-attribute damage against one target, though its exact attribute varies from game to game. For example, in Persona 5 and its spin-offs, Eiha inflicts Curse damage, while in Megami Ibunroku Persona, it inflicts Death damage. Also in Megami Ibunroku Persona, Eiha deals light damage against one target each turn, as opposed to its single-use effect in other games. The Eiha line of skills also appear in Persona 3 Reload as Dark-attribute skills.[1][2]
For more information on this subject in Super Smash Bros., see Eiha on SmashWiki.
Eiha is Joker's side special move, firing a weak darkness-attribute projectile forward that will deal damage over time to an opponent struck by the move. When his Rebellion Gauge is full, he will summon Arsène and the move will transform into Eigaon.
Trivia
In Super Smash Bros. Ultimate, despite being based on the Persona 5 incarnation of the skill, Eiha will cause damage over time, which only occurred in Megami Ibunroku Persona.
Nomenclature
Names in Other Languages
Language
Name
Meaning
English
Eiha
Transcription of Japanese name
Japanese
エイハEiha
Shadow Wave. From 影 ei, "shadow" and 波 ha, "wave" by analogy with 光波 kōha, "light wave".