Anime: Eyes and Transformations
Eyes are essential in seeing and also in transforming. The transformative nature of a character can be seen as a power boost or an incomplete status that could damage them. These transformations are where the eyes change and give them an image associated with the newfound power.
Akihito Kanbara (Beyond the Boundary) is a member of the Literary Club and is a half-youmu. Youmus are catastrophic illusions that seek to possess humans giving them a hostile nature and are targeted by Spirit Warriors because of this phenomenon. He turns into this state when Akihito gets severely injured and the youmu side comes out. In the half-youmu state, Akihito has great healing capacities and becomes a being with black eyes, blonde hair with green highlights, and mysterious green energy surrounding him.
Seras Victoria (Hellsing) is a former gunshot victim who was turned in an immortal creature of great power. Seras were held hostage by a vampire priest and as such eyes turn from ocean blue to blood red. As a vampire, she has enhanced strength, reflexes, power over souls, everlasting life, and other vampire abilities.
Ken Kaneki (Toyko Ghoul) was a student at Kamii University until the fateful day of meeting Rize Kamishiro. Rize changed Kaneki's life in many ways than one like for instance a half breed. He undergoes a transplanted Ghoul (a human-like creature who eats humans) transformation as a half-human and half-ghoul. This earned him the status of the first artificial one-eyed ghoul which he covers the red-eye by an eye patch.
Annie Leonhart (Attack On Titan) earned the fourth rank in the Military Police Brigade and is characterized as a lone wolf. She takes on the form of the Female Titan where she fights in martial arts combat and hardening abilities. In human form, the eyes are blue while the Titan form is giant green eyes.
Howl Jenkins Pendragon (Howl's Moving Castle) is a powerful wizard who goes by many names and spreads rumors to keep his privacy. He has a curse that the Witch of the Waste cast upon him to return to her. The curse changes Howl's appearance by feathers and black blue eyes than bright blue eyes.
Anime is filled with transformations and power-ups for characters to the point of insanity. Without changes in appearance, anime would not be the same for these changes are signs of growth in characters. Finally, the eyes that are coming next are where holders of eyes are hunted down.