Ornate War Sword
The Ornate War Sword (also known as Fireblade V3) is currently the most powerful pet weapon.
Hail the Roaming Gnome in Tower of Frozen Shadow for details about the quest.
You will need the Ceremonial Wedding Sword from Nosja or Daman on Tower of Frozen Shadow Level 5 to complete the quest.
Once completed, hail your pet and click the arm yourself link to have them equipped.