Zelgius

Zelgius (ゼルギウス, Zerugiusu?), better known as the Black Knight (漆黒の騎士, Shikkoku no Kishi?), is Daein's most powerful general. The Black Knight's identity is never spoken of in Fire Emblem:Path of Radiance, save for the fact that he was once a student of General Gawain. He is also a branded, which he revealed to Sephiran, who provided him with his sword and armor.

Fire Emblem: Path of Radiance
At the beginning of Fire Emblem: Path of Radiance,he is the most powerful of Daein's Four Riders. He wears a special suit of full-body black armor that has been blessed by the goddess, making it impenetrable to all weapons save those that have also been blessed, such as Ragnell. He also has access to numerous other arcane items as well, such as the Warp Powder he uses to travel, his sword Alondite, and the sword Ragnell, which he gives to Greil seemingly as an act of mercy-- but mostly for an interesting battle. After killing Greil, he becomes Ike's mortal enemy, and the Black Knight spends much of the game performing acts to enable Ashnard's efforts, such as providing Ashnard with blessed armour much like his own.

Ultimately in Chapter 27, Ike faces off against the Black Knight in a duel (Mist accompanying Ike), and Ike wins (according to canon). However, the player does not have to defeat the Black Knight, as the castle automatically collapses at the end of the fifth turn. Regardless of whether or not the player is able to defeat the Black Knight, traps are set off in the fortress, burying him.

Ashnard, after a comment from General Petrine about the Black Knight's strength, said he would be interested in challenging the Knight some day.

Fire Emblem: Radiant Dawn
As the Black Knight, he returns in Fire Emblem:Radiant Dawn to protect Micaiah when Jarod attempts to kill her and continues to protect her both in the final battle against the Begnion Occupation Army and in the war against the Laguz Alliance. As Zelgius, he leads the Begnion Central Army against the invading laguz. He serves Prime Minister Sephiran selflessly and views him as his master. All of his actions are guided by Sephiran's will, including his eventual return to Daein as the Black Knight.

Zelgius's only goal was to face Gawain at the height of his power; his pursuit of this duel was the only action he undertook of his own accord after becoming Sephiran's follower. However, upon finding that Gawain was not at his true power, he seeks out Gawain's remaining student, Ike, facing off against him in a one-on-one fight. Ike defeats him; Zelgius dies believing that Ike fought with all of the skill Gawain possessed in his prime, and rests peacefully, waiting for Sephiran to join him. Ike considers Zelgius his final teacher.

Other Appearances
In the Wii game Super Smash Bros. Brawl, the Black Knight makes an appearance as a trophy, but in his description, he is falsely stated as the wielder of the sacred blade Ettard, while he actually wields the sacred blade Alondite (although the names were switched between the JPN and Western releases, so this was true for the original version).

Starting Stats
|Black Knight |20 |70 |38 |18 |40 |30 |20 |35 |25 |6 |Sword, Lance