Used to be Tashki's strongest form. Though the Ehrall is unknown and unmastered by anyone, Tashki was the only one who has mastered it, and has defeated Absolutus Malum: Omnis Finem once and for all.

 

Though despite of this as her strongest "form", it was then clearly known that it is only needed when it's absolutely necessary. Especially since Tashki has found something else that might possibly be better.

With Malum destroyed by Reimu/Tashki, Tashki has sealed both the Ehrall and Malum's powers away amongs the Eternity, keeping them fully neutralized and at rest to hopefully be of no more use. Thus Labyrinth/Malum was eradicated by Reimu/Tashki's Fantasy Nature within the Eternity, in order to prevent another Great Incident.

Ever since then, it was believed Malum would cease to exist. But rumors and legends speak of a one possible legend...the Dark Legend that would alter even the fabrics of all Existence and Non-existence. The only bearers of such a thing, are the Souls of Evil in which stand today against the Great Four.