I couldn't finish 'em. Looks like this's gonna get complicated.
Spawned by the god of earth, this dragon uses Earth Eye to boost all foes' vulnerability to earth, then paralyzes them with an earth shock wave from Megaton Press.
Ladon is an optional boss in Bravely Default. One of the six keystone guardians, it guards the Earth Keystone.
Ladon has three abilities at its disposal. Bite deals damage to one target, Earth Eye makes the party Earth-Weak, thus lowering their resistance against its powerful Megaton Press ability, which deals earth damage to all party members and can inflict paralysis.
Two Templars and two Spiritmasters with White Magic are the perfect counter to Ladon. The Spiritmasters should apply Fairy Ward to prevent Megaton Press's paralysis from crippling the party, and should reapply it whenever necessary. The Templars should focus on keeping Rampart up at all times, to minimize damage. The Spiritmasters will be the primary means of offense, using Fairy's Aid and Aeroga to deal large amounts of damage to Ladon. Fairy Ward will not protect against Earth Eye's Earth-Weak status, but giving party members the BP Recovery support ability will turn this to the party's advantage by granting them 2 BP whenever Ladon uses that ability.
One could also have three level 7+ Templars and a high level Monk. The Templars should take turns using Rampart while the Monk uses pressure point. If one buys four Earthing Rods in Florem, the paralysis is not a problem. This strategy can be used for all of the keystone guardians.
One could also have all party members as Ninjas at level 5 making use of Utsusemi and Transience. Use Utsusemi at the beginning of battle and Default when possible. Building up BP will allow one to attack or recast Utsusemi when attacked. This method is more effective if paired with Spell Fencer or Ranger abilities to take advantage of class weaknesses. In addition, the latter has access to Paralyze Immunity, which will prevent Ladon from paralyzing.
A single Ninja with Turn Tables, Comeback Kid and Transience can easily take down Ladon by itself. Simply make sure Utsusemi is always up and attack whenever BP allows it. Never go below -1 BP however since that means Ladon can attack several times thus penetrating the Utsusemi defense.
Ladon was the serpent-like dragon that twined and twisted around the tree in the Garden of the Hesperides and guarded the golden apples.