Right after Octavia struck the deal with her ego weapons, she went to report the incident to Asher. This is only fitting since the necromancer needs to know everything that goes on in their group in order to create the best improvement plans for everyone.
Hence Asther was told about the deal that was struck. How she would undergo the process of hybridization little by little. How her weapons agreed to let her use their skills while this is still going on. And how they would only accept her as their master once Octavia has actually turned into a full hybrid.
These are the conditions to using the double ego weapon. Asther thought that this is a good bargain on the female knight’s part. Especially because, at the moment, she doesn’t have the strength necessary to dominate the said weapons.
