Amnael

Amnael「アムナエル」(Amunaeru) is the seventh and final Shadow Rider, who challenges Jaden Yuki after defeating Alexis Rhodes and Chazz Princeton, while also taking Atticus Rhodes hostage. They are sealed in his Emerald Tablet Shadow Charm. It is revealed that he was the one who took Atticus to the alternate dimension and the latter was forced to use Nightshroud's mask card.

There, Nightshroud got his Shadow Charm medallion. It is also the same place where Banner took Jaden in episode 28 and where Jaden gets the other half of Nightshroud's shadow charm.

"Amnael" is actually a pseudonym used by Lyman Banner as his old body was suffering from an illness so he created a homunculus clone of himself and placed his soul inside the vessel, but his new body was only temporary and was crumbling away. In order to survive he joined the Shadow Riders to free the Sacred Beasts so that they would support his body to keep it from turning to dust.

Banner overpowers his former pupil with his Alchemy monsters and taunting Jaden, but Jaden manages to Summon "Elemental Hero Electrum" which counters Banner's strategy and defeats him.

After giving Jaden his Shadow Charm, the Emerald Tablet, Banner turns to dust, along with his original mummified body. His spirit, however, is swallowed by his cat, Pharaoh, which went unknown to the rest of the characters until season 2. Banner's Shadow Charm would help in Jaden's Shadow Duel with Kagemaru as it held "Philosopher's Stone - Sabatiel" which gave Jaden the power to defeat the Sacred Beasts.

Non-canon appearances
In Yu-Gi-Oh! GX Tag Force, Amnael appears in the game's third part and duels the player and his partner alongside a brainwashed Jaden Yuki. After completing the game once, he can be selected as a partner should you defeat him in an individual duel. You can also see him in Abandoned Dorm after you complete the game.Only in 10.00p.m.

Anime
Amnael plays an Alchemy Deck, which draws a relationship between the science and universe. His strategy relies on the removal of his own cards from the game, supported by the Special Summoning of Alchemy Beasts (Alchemic Beasts; 「錬金獣, Renkinjū」), based off common base metals and animals used in alchemy to transmute and refine gold and the Alchemic Processes, based off 4 of the 7 main stages in transmutation, falling under calcination, dissolution, separation, conjunction, fermentation, distillation and coagulation. In the Japanese Version, the positions of the 2 words making up each Alchemic Beast's name are inversed, as well as "the" being omitted entirely. (Their names, as well as the names of the Alchemic Processes, are not hyphenated.)

Tag Force
In Yu-Gi-Oh! GX Tag Force, Amnael uses 2 Decks, both of which focus on powering up his monsters via removing cards from play. The Decks utilize cards from the "Different Dimension" archetype in place of the anime-only Alchemy Beasts, though "Alchemic Kettle - Chaos Distill" and the "Helios" series are included.