Previously, Reiji had never thought of having Shiori summon an Arcana.
After all, she's just a Sword Slave… Someone whose death was guaranteed after leaving him at a certain distance.
However, because of the limitation being removed after reaching the Legendary Rank Arcana, Shiori can now freely move and she's also someone that will never betray him. She can be trusted to deal with various tasks that require secrecy.
In short, making her stronger will only benefit Reiji.
Even if she dies, the Arcana that she summoned can still be used by his disciples or any one of his capable Sword Slaves.
With that in mind, Reiji made sure to act on it once they are in the city.
After about half an hour of fighting against the horde of Orcs, they finally managed to kill the last one who had tried to escape after seeing that everyone else are dying.