I got a gut feeling Cozy Glow was hiding in g1 of My Little Pony. After Tirek was gone, Megan and the other ponies banish her and other ponies who are loyal only to him. She hated Firefly and Megan for what they did to her mentor and friend.

Firefly(walking in dream valley): I wonder what are the Grundles up to.

Cozy Glow swoop down at the ground in front of Firefly.

Cozy Glow: Hello Gerald Firefly.

Firefly: Cozy Glow?! What are you doing here?! You were banish with the rest of the outsiders!

Cozy Glow: I was just flying by when I heard about the grundles, and wondering why aren't you in your castle.

Firefly: We give our castle to them. Their home were destroyed so, but we live in Paradise State now!

Cozy Glow: Why you give your castle to those monsters! You couldn't be more powerful in that castle!

Firefly: Shut up Cozy! Just because you're an alicorn you can't decide what us to do!

Cozy Glow: Lord Tirek made me an alicorn. He wouldn't be alive if it haven't be for you and that human!

Firefly: Get lost Cozy Glow!

Cozy Glow: Fine, but remember this Firefly! I will return with an army, and we will take you down!