Prelude to Destruction (破壊の序曲 Hakai no Jokyoku) is a technique used by Whis.
In the Finger Beam versions, Whis holds out the index finger of his right hand and fires a light blue to bluish-green energy wave from his fingertip.
In the Energy Sphere version, Whis creates a blue energy sphere which he fires from both hands at his opponent.
Video Game Appearances
Prelude to Destruction was named in Dragon Ball Heroes, Dragon Ball Heroes: Ultimate Mission, and Dragon Ball Z: Battle of Z, where it is Whis' super attack and Blast Spark. In the latter, it is the blue Energy Sphere version which is used, rather than the Finger Beam version.
In Dragon Ball Xenoverse, Prelude of Destruction is Whis' Super Skill and takes the form of an bluish-green Finger Beam which is powerful enough to knock back opponents and causes a decent amount of damage, though this is offset by its somewhat slow startup. The Future Warrior can also obtain this skill as a reward in Parallel Quest 43: "Old Rivals and Dragon Balls". It is also used as Whis' Super Attack in Dragon Ball Z: Dokkan Battle.
"Fires a Ki Blast that puts the opponent in guard break status if it hit. Will not break an opponent's guard."
— Dragon Ball Xenoverse 2 Tutorial description
In Dragon Ball Xenoverse 2, it returns as one of Whis' Super Skills. It is capable of putting an opponent in Guard Break status if it hits an opponent while their guard is down (as it cannot actually break through their guard). As part of the Masters Pack DLC, the Future Warrior can learn this Super Skill by completing School Quest: "Lesson 1" of Whis' Training. It is among the few skills that cannot be transferred over from Xenoverse.