So with the scene taking place on the Turtles' Third Earth instead of the Humanimals' First Earth is significant as it already gives the younger less advanced Earth a hint that there are 'Skeletons in the Heroes' closets' and that the this older universe is deliberately hiding things from them in order to make a good impression
Peter dropped his microphone on the floor, the sound was practically deafening! Whatever appeared seemed to suck all the magical energy out of the area, so Marzipan who was floating quickly fell, as a Cat Humanimal she landed on her feet but still it was scary!
All the Third Earth Mutants and humans gasped at what they saw! What seemed to have suddenly appeared on stage was an enormous living shadow! It's shape had the wings and hooked beak of a bird of prey and the lower half was that of some kind of big cat, those who were informed would be able to recognize the shape was that of the Mythical creature the Gryphon...And while the Third Earth citizens had seen among the Humanimal species were other mythical species like unicorns and dragons, but some were beginning to realize they hadn't yet seen a Gryphon…
The Turtles, after getting over their initial shock at this strange Shadow Gryphon suddenly appearing on stage, quickly drew their weapons and jumped onto the stage! Ichabod, his despair over being human briefly forgotten over the sheer shock looked at his Herd Siblings, they were all trembling violently!
Leo pointed a Katana at the strange shadow creature "WHO ARE YOU?!" He bellowed
"I am merely a ghost of things past…" The Shadow Gryphon chuckled in a contralto female voice "...Your physical weapons can no longer hurt me…"
"What do you want?" Leo asked narrowing his eyes
"Justice…" The Shadow Gryphon hissed "...Justice...For my murder…"
"Well who murdered you?" Ichabod asked initially thinking this was just a lost Humanimal Soul who needed help.
"THEM!" The Shadow Gryphon roared pointing at Ichabod's Herd Siblings all cowering in a corner "They who claim to be the Saviors of Humanimal Kind! They killed a fellow Humanimal!"
The Shadow Gryphon's roaring filled the audience with so much fear it seemed to flatten them against the ground, while the Turtles' also trembled they remained standing…
Ichabod was initially shocked by this revelation that his Herd Siblings would kill a fellow Humanimal, but Marzipan despite her fear stood up and said "Well what was the context? Maybe you deserved to be killed…"
And the Shadow Gryphon turned to the Pink and Purple Cat-Girl, and Marzipan having regained some of her bearings after the shocks and beginning to form a fireball in her hands and said "I warn you, I'm a Mage Monarch…"
And that seemed to shock the Shadow Gryphon and she vanished…
DUN DUN DUN! So now the Mystery has been revealed!