3rd POV
Y/N got out of the bed and his scales began to show more. His eyes flowed purple as the skin on his back began to break. Y/N got up from the bed and pulled the tubing off. Small wings popped from his back as he opened the window and jumped out it. He went to close the door to see Velvet walk in.
Velvet: Y/N, can we talk?
Y/N looked at her and sighed.
Y/N: no.
He closed the window and let out a massive roaring scream as his skin turned black and his eyes glowed. The massive black dragon shot upwards and flew off. Talzrentin flew off towards his cave and roared out into the sky as it flew, the power of the roar shattering most of the windows in Vale.

[There should be a GIF or video here. Update the app now to see it.]

(First roar in the video if you're interested)
Velvet looked out the shattered window to see Talzrentin flying off.
Velvet: Damnit!
She quickly covered her mouth to realize what she said.
Velvet: Sorry.
She ran out of the hospital room where Coco sat in the chair.
Coco: what was that sound?
Velvet: it was Y/N! He left the hospital and flew towards what I can assume is the direction of the cave.
Talzrentin stopped in his cave and walked in, seeing a few people by his gold. They all turned around to see the black dragon looking at them with the angry purple eyes.
Talzrentin: you four have chosen.....death.
Talzrentin lifted his wings and caused darkness to spread through the room, the four thieves unable to see. The last thing that could be heard was their screaming. The darkness disappeared as their bodies were gone without a trace, and Talzrentin walked over to his gold and began to swallow them, not eating, but to hold them until he finds a new cave, one where people won't find him.
Meanwhile
Team CFVY flew in a bullhead with a pilot towards the cave where Talzrentin was. The radio went off with an angry Glynda Goodwitch.
Glynda: TURN IT AROUND NOW! I KNOW WHAT YOU FOUR ARE DOING AND I WILL NOT STAND FOR YOU GOING!
Coco: mute that, so you think he's going to be there?
Velvet: I hope so.
Yatsuhashi: Velvet should talk to him if we find him, from what I could see, she's the only one that he somewhat willingly talks to.
Velvet opened the bullhead door as it opened and ran inside the cave, only to see that it was completely empty, no gold or trace of Talzrentin.
Velvet: he's gone!
She ran out of the cave, and in the distance heard the sound of water splashing, causing her ears to perk up. She ran away from the bullhead towards the sound.
Coco: Velvet!
Velvet: Go without me! I need to see if it's him! I need to ask him something.
Coco: don't get killed!
She ran and saw a cave with water in the entrance. She planted her feet into the water and made her way inside the cave.