Not Emerald, but Diamond
Ultima laughed heartily at Aster's outburst, while Scrierea wore a bewildered look. She then walked over to Ultima and slapped his arm, to which he almost immediately stopped laughing, but his eyes still conveyed his unspoken laughter. Sora also laughed at Aster's outburst, but a little more softly than Ultima, in fact, one couldn't hear her laughing over Ultima's.
"What's going on you ask?" Sora chuckled out, "Why, we're introducing ourselves, seeing as you'll be here for a while."
"I know that!" Aster said frustrated, "I meant, what is all this? How can you be so sure about me? How do you know of my blood? How do you know it's true?"
"Whoa, whoa slow down there!" Scry said suddenly, "We may be superhuman, but we can't keep up with that mouth." Unknown to Aster, his words were steadily starting to increase in speed, thus allowing to speak at superhuman speeds.
"How about we show you something." Ultima proposed. "Let us take you to the statues on the roof, and then you'll see something interesting."
"Okay then." Aster said, and he got up and followed Ultima to the roof, followed closely by Sora and Scrierea.
Now that he had a closer look at the statues, he could tell the differences. He could see that the topaz phoenix was glowing dully, and the red phoenix had what looked like a flame on the inside. The turquoise eagle had a constant thermal air current spinning around it, and the emerald dragon had electrostatic discharge running around it erratically.
"Okay, now that we're here, tell me what you see on the statues, and make sure that you look closely. Be sure you look at the sky dragon first though." Ultima instructed.
Aster looked at the emerald sky dragon and saw an indentation in the shape of a hand, and then he moved to the other statues and saw similar indentations on them as well.
"You saw a hand-shaped indentation on the dragon right?" Ultima asked, "But not on the others, correct?"
"No, I saw indentations on all of them." Aster said, "What does that mean, Ultima?"
"You saw them on all of them?" Ultima said confusedly, "Okay, then come with me. Sora, can you go and grab Voltic? Tell her that her elemental station is safe, and that we need her to get into the chamber of the Diamond Dragon."
Sora nodded once and took off with a gust of wind. Ultima motioned for Scry and Aster to follow him and they did. He led them through the fortress until he got to a giant door covered in crystal. There were five colored crystals on the door itself, one topaz, one emerald, one turquoise, one ruby, and one blue, like a diamond.
"This is the chamber of the Diamond Dragon." Ultima said, "Aster, what I had you do, was a test. I said earlier 'we have all but the dragon' but what I really meant was this dragon, not the Emerald Sky Dragon you saw on the roof."