I just saw the first (awesome!) episode of the Magicians S2 and I can't see exactly what I missed. Last we saw, Julia held the Leo Blade to his throat at first, yes, but after they vanished, he was in complete control right till they made their deal at the table. Why did he agree to her terms? Why not just kill her in transit or as soon as they arrived on Earth, and take the blade? What did I miss? Did she cast some temporary enchantment already before threatening him with the Blade?
As Julia was raped by Renard the fox she had the powers of a demigod. Renard was a demigod and son of Our Lady Underground, Persephone. And as we can see in last episode of season 1 that by drinking semen of Ember the god of Fillory Alice gets the power, so Julia also gets the powers due to having intercourse with Renard and so the Beast can't easily kill Julia. To prove this claim it is shown later in the second season that they were not able to kill the child of Julia easily, as it is difficult to kill Gods or persons with godly powers. Julia got godly powers from Renard.