Wow, did I just say that?
In Season 1, he has pointy ears, dark colored eyes, long dark orange hair, his bangs split in the middle and swapped to each side. His build is skinny and he wears a pale yellow long sleeved puffy collared shirt, with a red bow, a dark olive collared vest, light brown pants and shoes with red above-ankle socks.
From Season 2 onward, Palladium now has light colored eyes and is more muscular; his hair is still long but it is now a lighter shade of orange and has yellow highlights on both sides of his head and he now has side burns. He wears an ivory puffy long sleeve collared shirt and pants, a teal ascot, green vest and knee-high tan boots.
During the first season, Palladium was not a very confident teacher and although very nice, his students did not respect him and treated him more like a pushover. However, he is shown to be capable fighter seen when the Trix's sent the Army of Darkness to Alfea. He also displays that he knows quite a lot about nature.
In the next season, his appearance changed as well as his confidence, causing his students to respect him as he could now harshly scold and penalize any of them if they misbehaved, but he always gives stern warnings beforehand. He’s just a fun professor. He is kind and gentle, but isn’t afraid to give constructive criticism and to step up and fight evil.
In the first season, Palladium can be seen as a very nervous teacher with less confidence compared to the other teachers. He teaches Potionology. He takes the first year class out on a field trip to Black Mud Swamp where he instructs them to find their way using only the voice of Nature to guide them. Palladium is also the only teacher who is seen running the Simulation Room.
He aides in the battle against the Trix and celebrated their success with everyone at the end of the season.
In the second season he appears to be much more confident and muscular, having evolved his form since he's an elf. The evolution also caused him to be more strict with his students should they get out of line, case in point, when Amaryl was about to attack Stella, he stopped the spell and he threatened to expel Amaryl. He is also shown in various scenes with Professor Avalon, and when Avalon gets spit into his eyes by a plant, Palladium heals him. He teaches second-year fairies technical charms.
Palladium is rarely shown in Season 3 along with most of the other teachers. He is only shown in the background or in more unnoticeable roles.
In the episode "Alfea Under Siege" he and some of the students create a new magic barrier after the bewitched witches attacked and destroyed the original barrier.
Palladium has but a few amount of appearances in the fourth season. In the first episode, Tecna and Palladium had set up an obstacle course for the Winx Club to present before their students. In the second episode of the fourth season, he was setting up an AV for Faragonda's explanation of the Wizards of the Black Circle.
In "The Legendarium", Palladium is seen a few times during Faragonda's speech and anniversary party. He is seen again in The Secret Greenhouse where he is seen in a potion room transforming the Lorie, Evy and Carol back to normal after the Trix had turned them into frogs and helping Roxy turn the crow back into normal. He also gave the Winx information about Eldora that she was once a teacher here at Alfea and that she had a greenhouse that still exists at the school.
Palladium was seen running the Magical Reality Chamber as his students watch him. His appearance is redesign like Season 2.
Palladium appears briefly, as he is seen fighting against the witches' siege at Alfea. He wields a sword and fights against the army of darkness.