Gryphon

The main narrative is set in a mythical land where, about 300 years before, two princes named Lock and Delphus fought for their father's throne. Although Lock killed Delphus in single combat, their father's kingdom of Vallon was torn into rival nations, Lockland and Delphi.The story flashes forward from this prologue to the eve of Lockland's destruction, when the castle is besieged and the crown prince, the last surviving son of the King of Lockland, is killed in action by invading Delphites. Against the counsel of the prince's sister Amelia (Amber Benson), their father, the Locklander king, turns to his chief sorcerer Armand (Larry Drake) in despair. The sorcerer convinces the king to give him a handful of his blood with which to animate a stone statue of a gryphon, a flying beast that is the totem of Lockland. Using the blood to bind the gryphon to him, Armand first orders it to break the Delphite siege, then betrays his king and calls it back to attack the Locklanders in a coup. It is seen that the sorcerer suffers the physical effects of any attack against the gryphon, but regenerates almost immediately due to his bond with the beast.Princess Amelia escapes during the takeover and pursues the retreating Locklanders, led the Delphite prince Seth (Jonathan LaPaglia), who had been in the vanguard of the besieging forces. Having inherited the gift of magical visions from his parents, the prince is advised by his mother Cassandra (Sarah Douglas), a sorceress, to seek an artifact called the Draconian Pike, the only weapon that can kill the gryphon. His mother warns him that he must retrieve the two halves of the pike and reassemble it to kill the gryphon before a solar eclipse occurs in two weeks, or Armand will be able to enact a ritual that makes himself and the beast immortal.Amelia and her retinue capture Seth and his man-at-arms, David (Andrew Pleavin), during a night raid on their camp in a location called The Valley of the Dead. They locate the haft of the Draconian Pike in a centuries-old temple. Fending off an attack by the gryphon by means of "dragon's fire" (apparently black powder or an explosive variant of Greek fire), they escape and move on to seeking the blade. Meanwhile, Armand attempts to foment mistrust between the two rival nations by killing a Locklander messenger and sending his body to Amelia's father, a threat against her life magically scored into his chest. The king of Lockland calls for his armor and mounts a counter-invasion of Delphi. Meanwhile, Amelia confronts Seth at knife-point in his tent, demanding that he tell her where the blade is, but she lets her guard down momentarily and he takes advantage, seizing the knife; they fall into an amorous embrace.That same night, Armand sends his two magic-wielding brides, Daphne and Kyra, to seduce one of the Locklander soldiers into stealing the haft piece from Amelia and Seth. When Seth and Amelia find it gone the next morning, they decide to send messengers to their respective parents to muster the combined armies of Lockland and Delphi. Amelia and her remaining knights attack Armand's lair, while Seth and his retainer David enter a magically-warded labyrinth to retrieve the blade.The two kings call a truce and their armies prepare for a massed assault, while the gryphon prepares to destroy them. Queen Cassandra of Delphi bids her husband farewell and rides into the deserted stronghold of the enemy. Once Seth retrieves the blade, he rushes to the sorcerer's lair to confront him, but finds his path blocked by the sorcerer's brides. Cassandra tells her son to leave the sorceresses to her and go to dispatch the gryphon, sacrificing herself in a magical strike against them.Meanwhile, Armand has captured Amelia and killed the Locklander knight champion, and demands that she become his bride. Seth and David arrive and fight with the sorcerer, but soon loses the blade of the Draconian Pike. Assembling the pike, Armand kills David and prepares to kill the Delphite Prince, but is persuaded to spare him by the surrender of Amelia. As the eclipse begins, Armand proclaims that he will soon become an immortal and that his progeny with Amelia will be the new Titans. As he walks away from the defeated Delphite Prince, his hand touches Amelia's belly and he realizes that she is already pregnant with the prince's child. Furious, he rejects her and prepares to kill them both. A struggle ensues and Armand again knocks the prince to his knees, but is unable to deliver the coup de grace because the Delphite queen's spirit still protects her son. The sorcerer calls the gryphon down on the prince, to whom the princess tosses the Draconian Pike. It appears as if Seth is charging for the sorcerer, but instead hops onto a rock and turns just in time to level the pike at the stooping gryphon, impaling it. The gryphon reverts to stone and shatters as it falls to the ground, while the sorcerer dissolves into a pool of blood.The armies of Lockland and Delphi rejoice at their deliverance, cheering as Amelia and Seth raise the reassembled Draconian Pike overhead to symbolize the reunion of the sundered kingdoms of Vallon. In a voiceover, Amelia proclaims that the curse of civil war has been lifted.

Question: What do Lock an Delphus fight for?
Answer: Their father's throne