EX Skill

EX Skill (EXスキル) is the collective name for the set of skills Zero learns from Bosses in the Mega Man Zero series.

Zero's EX Skills
Introduced in Mega Man Zero 2, there are a few differences regarding this set compared to those skills Zero learned in the X series. To learn these skills, Zero must defeat a Boss at rank A or S (Zero 2 and 3) or with a weather favorable to the boss (Mega Man Zero 4). Zero has the option to toggle them on or off as needed. Buster Shot skills can only be used one at a time, due in part to all of them being modifications to the charged shot and, in the second and third games, requiring the appropriate Element Chip in order to use.

Bosses
The name EX Skill also refers to the extra attack used by bosses when Zero fights against them with a Rank A or higher. Most of these bosses' EX Skills are the basis for Zero's own versions.

In Mega Man Zero 4, the Einherjar Eight Warriors only use their EX Skill if the weather from their stage is favorable to them. Other bosses, including the rematch against the eight warriors in the final stage, follow the same requirement from previous games.

Trivia

 * The name of the Mega Man Zero 2-4 bosses EX Skills were mistakenly replaced by Zero's EX Skills in the English version of Mega Man Zero Official Complete Works.