Previously

Ailsa and Yaana were a step late, but they subconsciously fell in step with Ryu. As far as they were concerned, this man was their grandfather too. How could they not show him proper respect?

The outline of Saint Tatsuya's silhouette started off blurred, but it very quickly took forward. The passive expression of a man getting on in years was the first thing to appear. It didn't seem like Ryu's grandfather was aware of his surroundings at first and it took him a while to regain his bearings. 

Unlike Grandma Kunan who had been able to trigger her own awakening with the appearance of the Legacy World, Grandpa Tatsuya's awakening was triggered by Ryu's appearance in this world. As such, he was still waking up even long after Ryu appeared.