Just a second after their voices, three people descended from the sky right at the entrance of the valley, Agnes had free access but she decided not to directly walk in, out of respect for Mikaela who was accompanying her.
The very moment the three newcomers became visible, Aster felt a surge of bloodlust coming from behind of him, which he easily recognized since it belonged to none other than that dragon sister of his.
Which is why he flashed towards Alice's side and wrapped his right arm around her waist, to prevent her from attacking the plus one that Mikaela brought as a guest.
In case you wonder why Alice reacted like that, that's because said plus one looked rather familiar, as it was one of the girls that appeared to cause trouble with Edward back then.