Progenitor God Ruptured Heaven

Progenitor God Ruptured Heaven (, Divine Progenitor Destroyed Heaven) is Byleth's Final Smash in Super Smash Bros. Ultimate.

Overview
Byleth begins by lashing forward the in its whip form, shouting "I'll finish with this!" (, I finish with this!). Sothis then appears in the background and bestows Byleth her power, temporarily granting him access to his appearance; Sothis utters "Your will and mine be now as one!" as she does this. Byleth then readies the Sword of the Creator before extending it into its whip form and lashing out once more with extreme force, while grunting simultaneously alongside Sothis. Sothis then says "The end approaches!"

Origin
This is an upgraded version of the existing Ruptured Heaven from Fire Emblem: Three Houses. Ruptured Heaven is exclusive to Byleth while wielding the Sword of the Creator. It adds 30% of the user's magic to the weapon's might and deals effective damage to dragon units. In Three Houses, Ruptured Heaven does have an upgraded version known as, attained as part of the upgraded Sublime Creator Sword when Byleth attains the Enlightened One class by fusing with Sothis in Chapter 10.

Sothis' first line of dialogue during the Final Smash are the same exact words she speaks before fusing with Byleth in a cutscene from Chapter 10 albeit more intense than the original. The second line she speaks however is original to Smash.

Before Fire Emblem: Three Houses, it had appeared in Fire Emblem Fates and Fire Emblem Heroes under the names Rend Heaven and Ruptured Sky, respectively. In the former game, it is associated with the Basara class, having the ability to add half of the enemy's strength or magic to the user's own strength or magic (depending on whichever stat the skill's user is currently using to attack the enemy). Conversely, the latter depicts it causing the user's damage output to be boosted by 20% of the target's Attack, and further boosting it to 40% if the target is a non-human foe. This form of the skill is considered to be an upgraded form of Draconic Aura.

Trivia

 * Byleth will attain light-green hair, a result of merging with Sothis in Three Houses, regardless of the costume selected. This includes the two costumes that already have light-green hair, meaning no changes happen with them.
 * Byleth temporarily attaining this hair color during this Final Smash ironically makes it impossible for this attack to be in canon, as it is replaced with  once the merge is complete.
 * Sothis' appearance in the background consists of a simple animated image. As a result, it can be easily swapped out with any image by modders, who often do so for humorous purposes.
 * Progenitor God Ruptured Heaven has the longest English name of any attack in the series, at 27 letters or 30 characters.