SPOILER!
If I understood well while using my pets and translator
(Thansfully, using English/French seeing extra
possiblity helped lots~ XP)
I found out 3 of them, but I used pets with 500/600+ in
the said stats, dunno if it's lower need :

Alacrity : Gave me "Speed" so Agility was my pick
Courage : What it gave me made me and my bf think of Strengh
Cunning : Dex, first though it was Int, but seem 233 or more is
good enough in that Stat~ :3
Perception : Had picked Dex, but seem it was INT, that was needed
here~ XD

Thanks Ekoyim~ ;3
(This have been Edited due to some mistakes~ XP)

EDIT :
(For those that might read only this...)
Seem that pets having 200 points or more into one said stat
are enough for each seals, as long as they have 200+ of THAT
asked stat~ ;3

Cunning = dex
Perception = int

I swapped those two

Well seem my Rano was enough to do the Cunning
part them~ XD
I just did 3 Full-Mana Finishing Blow on Mister the
King and he was under half his life even if Perception
"Buff" was still on, I ended up killing him, no idea what
Perception gave him(Maybe Magical Def? o.e), but he
died fast and I just killed the other two like any Undead~ XP

You don't need to break all the seals to beat him. It just makes it much, much easier. I forget what each one did but I believe one increased his defense, one increased attack, one let him endlessly summon undead if you killed them and I forget what the last one did.

I beat him with only breaking two as I swapped dex and int.

Well... still no idea what Perception does,
but seem my Rano, with his 233 Dex, was
enough for Cunning and broke that one,
even if I though it was Int(He's high in Int~ XP)

I just did full-mana Finishing Blow, making
his life go somewhere around 30 or 40% ish,
then just spammed Slash(Sligger and Draelie)
and Fireball(Rano), then he died fast and his
underling felt as fast~ XD

I believe it helped I have the top gear we can
get in Saerielle too, as it boost GREATLY my
pet's stats, up to now, I've fought with a bit
lower gear, but if I had forgotten again to
boost them, I would probably have died there~ XD
Just going to the seals~ XP

EDIT : Maybe one of the buff give Critical boost?
Would be crazy?
That or evasioness?! >:^O

Ugh, I really need help´with this stage, I don't seem to be getting anywhere here.

Well, I decoded the message and all, and after some tries that didn't work I came to the forums to check if I could use some help from you guys, but I see it's not working either =S

*SPOILER*

For what you have said, each seal is one of the pet's stats:
Cunning = dex
Perception = int
Alacrity = Agility
Courage: Strenght

And that to be able to activate them, the pet must have +200 in the stat you'll be using it for - very well, I equiped my pets Pandora and Doctor Who to emphasize their strenght and intelligence, respectively, and used my pet Poison's high level at agility (over 300 with equipaments), but no one of them worked either! What must I do? Does the pet need 200 POINTS in that specific trait? What am I doing wrong? =/

I'm having trouble with this too - equipped my pets to have above 200 points in the required stat, but it still won't glow for me?

If you translated the inscription, you'll know that they're not supposed to light up even if you got it right. The only way you can tell if they worked is if you go into the boss room and check the buffs on the boss, or if you got them all right consecutively, they should light up by the 3rd or 4th seal.

I think having a separate pet with 200 single points in a stat SHOULD work. But you can't tell by the seal you see alone. Just because it doesn't light up doesn't mean it didn't work.

Oh boy! My bad - and you did catch me there, I fail horribly at the translation, so I kind of went with the posts here haha.

Thank you so much for the reply!

If you get them all correct, they do light up though. I saw them do it...

They just light up only if you have /all/ of them broken. If you get one right, but the others are still wrong, none will light up.