Gideon

Gideon was a former Elder and friend to the Charmed Ones as well as Leo Wyatt. Later, Gideon became afraid of the power granted to Piper and Leo's first-born child, Wyatt Halliwell, believing that the child had been born with too much power. This resulted in him plotting to kill baby Wyatt to stop the dark future from ever happening, and ultimately protect the greater good. His efforts ultimately failed, which lead to his death at the hands of Leo Wyatt.

Personality
In some ways, Gideon was a champion for the Greater Good - even to the point of obsession. He was a strong Elder and a very intelligent teacher, able to balance everything and still have time to help the Charmed Ones with their magical woes. At some point, he became very aware of the kind of power Wyatt Halliwell possessed, decided to kill baby Wyatt, as he believed that the child had to much power. his mental mind-state was anything but stable, as he consorted with demons such as Barbas, the Demon of Fear, to get ahold of Wyatt to kill him. He also pretended to be the Charmed Ones and Leo's friend, all while acting innocent and oblivious to anything regarding the "demon" after Wyatt.

Professional Life
Prior to his death, Gideon was a dedicated protector of the greater good. He was the first Headmaster of Magic School and fought for the school against the other Elders. He was also an Elder and made it his goal to kill baby Wyatt.

Physical Appearance
Gideon was a mildly attractive man in his mid-late forties with thinning brown hair, bird-like brown eyes, and pale skin. He had a small mustache and beard combination. He was normally seen wearing a suit and tie along with a long black cloak, as that was considered tradition clothing for a Headmaster.

Powers
Since Gideon was an Elder he had possessed Elder powers and possibly some Whitelighter powers. Gideon most likely was also able to cast spells, brew potions, and scry.

Notes and Trivia

 * Gideon has mentioned watching over Prudence, Piper, and Phoebe since the girls were born.
 * He can be considered a tragic-hero as he believed that everything he was doing was for the greater good.
 * Gideon is directly responsible for the death of dark-future Chris. However, while Chris may have died (or at least vanished) he was reborn into the good future, thus resetting his life and timeline.
 * He is the first known Elder to be killed by another Elder.
 * He is the first on-screen character to be killed by Leo Wyatt.