Old Dragonslayer

The  is a boss in Dark Souls II.

General Information
The Old Dragonslayer can be found in the Cathedral of Blue past a total of 9 Old Knights  (if not killed for good). He can be found by going in the opposite direction of the Dragonrider and killing the Ancient Knight next to the lifted drawbridge to raise a lever, activating it will lower the drawbridge allowing the player to fight him. The Old Dragonslayer's moveset is nearly identical to Dragon Slayer Ornstein's with the exception of magic attacks.

Summoning
Masterless Glencour can be summoned from a ledge just to the right of the Dragonrider's arena. A fearless tank knight wielding a greatsword and a shield, Glencour will immediately rush the Old Dragonslayer after stepping through the fog gate, and continue to distract and inflict moderate damage throughout the battle, making him an invaluble ally to those having trouble conquering the Old Dragonslayer in a one-on-one situation.

Strategy
The fight is very similar to the Dragon Slayer Ornstein and Executioner Smough fight without Executioner Smough. There are slight differences in how the Old Dragonslayer fights compared to Dragon Slayer Ornstein. An example would be that the Old Dragonslayer uses a magic attack, where Dragon Slayer Ornstein did not. Aside from that attack, the fight is essentially the same, with the same sort of movement and similar attack patterns as Dragonslayer Ornstein uses in the original Dark Souls should the player have slain Executioner Smough first.

Blocking until the Dragonslayer misses an attack may prove to be beneficial to the player, as well as backing away when he begins to cast his magic attack. Using a bow or crossbow may result in being able to stun lock him by shooting him in the head. The Old Dragonslayer is weak to magic. He is also vulnerable to lightning-based attacks.

Trivia

 * The Old Dragonslayer is reminiscent of Dragon Slayer Ornstein from Dark Souls.
 * The Old Dragonslayer uses Abyss attacks similar to Knight Artorias.