This was originally going to become Rose's new Mega form but I decided to keep the canon Mega form but still design my own.

I based the basic design on the Mega form but made Rose, bigger and stronger. She now stands at a towering 25 feet tall. I always saw the next stage in a houndoom's evolution becoming a Cerberus so I went with the 3 heads on this. Her little bone accents have grown into a tough set of armor and reflects her Dark/Fire nature.

This form is powerful but can be quite exhausting if used too long. Activated by a Dark Legendary stone, Rose becomes a Dark Legendary pokemon for a short time.