I couldn't finish 'em. Looks like this's gonna get complicated.
This dark dragon lives for the carnage of battle. It uses Evil Eye to boost all foes' vulnerability to dark, then strikes dread into them with Fearsome Breath.Bestiary
The Jabberwock is extremely powerful, and has three abilities of note. Its Bite attack deals heavy damage to a single target, its Evil Eye ability inflicts the Dark-Weak status on the entire party, and Fearsome Breath is a physical attack that deals heavy dark damage to the entire party and inflicts the Dread status.
Though the Jabberwock's attacks are powerful, there are a number of ways to negate most of the danger it poses. The Ninja's Utsusemi can prevent that character from taking damage from either Fearsome Breath or Bite, and Transience and Counter Amp can lead to the Ninja counter-attacking for heavy damage whenever the Jabberwock tries to bite him/her. The Templar's Rampart ability can protect the entire party from the Fearsome Breath or Bite attacks, and its Radiant Blast ability deals Light damage, which the Jabberwock is weak to. The Spiritmaster's Spirit Ward or Greater Spirit Ward abilities can nullify the damage of the dragon's Fearsome Breath, and Adaptation can cause party members to absorb the damage instead. However, this will not prevent the damage of the Jabberwock's Bite attack.
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. This strategy can be used for all of the keystone guardians.
Jabberwocky is a nonsense poem written by Lewis Carroll in his 1871 novel Through the Looking-Glass, and What Alice Found There, a sequel to Alice's Adventures in Wonderland. In an early scene in which she first encounters the chess piece characters White King and White Queen, Alice finds a book written in a seemingly unintelligible language. Realising she is travelling through an inverted world, she recognises the verse are written in mirror-writing and holds a mirror to one of the poems, and reads the reflected verse of "Jabberwocky." She finds the nonsense verse as puzzling as the odd land she has passed into, later revealed as a dreamscape. The creature called Jabberwock is never fully described but is accepted to be an unworldly and vicious entity.