|“||Let us test your stronger arm then. Come, Son of Gawain, show me your strength.||„|
|~ The Black Knight|
Zelgius, usually under the guise of the Black Knight, is a recurring character in Fire Emblem: Path of Radiance and Fire Emblem: Radiant Dawn. He wields the sword Alondite and wears armor blessed by the Goddess, Ashera. He cannot be harmed by normal weaponry.
The alter-ego of Begnion's Military Commander, Zelgius, he was born a Branded (half-beorc and half-laguz), and ages more slowly due to his laguz blood. He wears his famous armor to disguise this fact from his fellow Daeins, who despise both the laguz and the branded.
He was trained by General Gawain (also known as Greil), whom he has always wanted to best in a duel to prove his strength. Even after Gawain left Daein, the Black Knight remained in service of the Mad King Ashnard. He is eventually approached by Sephiran, the Prime Minister of the Begnion Empire. Zelgius becomes commander of the Begnion Central army while the Black Knight remains the strongest of Daein's Four Riders. He uses warp powder to get from place to place. Although he has sworn loyalty to Daein, by the time the series begins, he is loyal only to Sephiran.
Path of Radiance
By chance, he meets his old teacher in Gallia shortly following the Daeins' invasion of Crimea. The two partake in a duel in which he offers Greil the sacred sword, Ragnell. Greil does not take the sword, because he obtained an injury to his wrist causing him to no longer be able to wield swords. The Black Knight is unaware of this and defeats him in the duel anyway. After killing Greil, with Greil's son Ike watching, he is not satisfied. Had his old mentor's skill diminished over the years?
Ike swears to kill the Black Knight for what he has done. They meet many times throughout Path of Radiance. General Zelgius leads Begion troops to capture Daein and Ike even thinks he is "trustworthy enough". Of course, he did not know that these two are one in the same. Only after Ike obtains Ragnell do the two finally duel at Naddos Castle. At this time, Ike explains Greil's injury to the Black Knight's distaste. After Ike has defeated him, the castle collapses on top of him.
The Black Knight didn't actually die. He appears three years later in Daein during its occupation by Begnion. He assists the Dawn Brigade in overthrowing Begnion's rule of their country. He spends the rest of the game aiding Michiah as the Black Knight and leading the Begnion army as Zelgius. A laguz named Ranulf discovers the link between the two and divulges this information to Ike.
After the Goddess wakes, he waits in the Tower of the Goddess until Ike appears. The two duel and Ike truly defeats him. As he lay dying, he tells Ike that he saw Gawain in his swordsmanship and is at peace knowing he has truly fought his mentor once more.
Fire Emblem Heroes
The Black Knight appears as a usable unit in the mobile game Fire Emblem Heroes. He is the third Armored Sword Unit and the first Armored Unit to be distributed as a Temple Trials unit. He is a powerful unit being able to not only tank attacks, but can dish out powrful attacks as well, thanks to a combination of Alondite, granting him Distant Counter, and his own unique Special Skill, Black Luna. He appears as both as the Black Knight and as Zelgius, the former can also be obtained in a $3.99 USD bundle which includes 12 Orbs, 12 Stamina Potions, 12 Light's Blessings, and 1 5-Star Black Knight. Jokingly, fans have compared it to a fast food combo, and due to the Black Knight having the same abbreviated letters as it, dubbed it a "Burger King Meal".
Super Smash Bros. Series
The Black Knight first appears in Super Smash Bros. Brawl as a trophy and a sticker, and is referenced in the playable song "Against the Dark Knight", a song which plays on the Castle Siege stage. Black Knight later appears in Super Smash Bros. for 3DS and Super Smash Bros. for Wii U, once again appearing as a trophy and having his theme being in the game. He also later appears as a DLC Mii Costume for the Mii Swordsman.
In Super Smash Bros. Ultimate, The Black Knight gets upgraded to an assist trophy. As a assist, he slowly moves around the stage while attacking nearby opponents with Alondite, his sword. His armor is again a Costume for the Mii Swordsman. Robert Clotworthy and Junji Majima return as the VA's of Black Knight by using recycled voice clips from Fire Emblem Heroes.
- The Black Knight drives much more of the plot than he is traditionally given credit for. He does a lot of work behind the scenes to fulfill Sephiran's designs.
- The Black Knight bumps into Sephiran by chance while fighting Ranulf. Sephiran tells him not to pursue Ranulf or the fleeing Greil Mercenaries and the Black Knight listens. This is the first time the player knows of a link between the two of them.
- The Black Knight and Sephiran once stumbled upon the site of a massacre. A town was destroyed by Greil's power alone. Greil's children, Ike and Mist, saw him kill their mother in a confused rage. Sephiran erased the childrens' memory of this and together they hid Greil from suspicion.
- General Zelgius refuses to kill the unarmed Queen Elincia and is almost executed by Begnion Senator Valtome for this act of chivalry.
- Zelgius has a loyal follower named Levail who is very much to Zelgius as Zelgius is to Sephiran.
- Black Knight's Path of Radiance incarnation came in 25th place for Male Characters in the Fire Emblem Heroes Choose Your Legends popularity poll, having 5,317 votes. Meanwhile, his Radiant Dawn incarnation was in 28th place for males, having 4,870 votes.
- For a unknown reason, Zelgius does not use Alondite while wearing his General Armor. However, this is most likely to hide that he is the Black Knight.
- In Radiant Dawn, due to the Black Knight being playable in some levels, the level of his lance is able to be upgraded. from S to SS.