After Irene casts Universe One and reconstructs Fiore, August calls all of Alvarez's forces and the Spriggan 12 to the newly relocated Fairy Tail guild hall. There, Jacob hears Ajeel proudly saying that Fairy Tail will never reach their guild hall and Mavis as long as he's there. Jacob remarks that Ajeel lost earlier to Fairy Tail, to which Ajeel angrily tells him that he lost too. Ajeel then says that it will not happen again, which Jacob agrees on. Then all of the Spriggan 12 stand alongside their emperor in a battle formation awaiting Fairy Tail to come and try to retrieve Fairy Heart.
As God Serena battles a newly arrived Gildarts Clive, Jacob comments on the Fairy Tail members' determination before getting punched by Mirajane, who tells him that she is his opponent. Jacob then turns to fight her but sees her nearly exposed cleavage, causing him to close his eyes and refuse to look at her. This causes him some trouble as it makes it hard for him to fight her. However, he begins to easily overpower Mirajane, even with his eyes closed. Their fight is interrupted by Irene's voice, who is trying to find an escaped Mavis, but Jacob pays no attention to this while Mirajane recognizes the voice. After Irene's death and the dispelling of Universe One, Jacob is defeated by Mirajane in her Satan Soul form because he refused to open his eyes during the entire fight.
Mirajane changes back while panting. She comments on Jacob's immense strength and says that if it wasn't for him closing his eyes, she would have lost.