Kill more enemies so that the master can reach master level at the end of his fight.
That's what all four familiars of Roy agreed before the fight.
"Hey. Let's kill a lot of monsters so that Roy can reach master level and add another monster as his familiar."
The one who suggested that idea was Victoria. Roy's first familiar. A Black Slime who was an Aura user in her past life. And in her past life before that, she was an ordinary woman from another world.
She might be teasing Roy a lot with her various knowledge from her original world. But she's someone who has been with him the longest.
She knows Roy's desire to destroy the cult. And she's trying to help him in any way she can.
And one way to do it is for her to kill more enemies. Because that's how a summoner can reach the next level. By letting their familiar to kill enemies.
