I'm stuck by the Demon Wall in Final Fantasy XII. It keeps healing itself before I can kill it. Got any advice

Question

Also, the levels of my characters are around 9-14.

Answer 1

which demon wall? if you're talking about the first demon wall, it's impossible to defeat it at this lvl.u need to defeat the second demon wall only. then, later in the game, u can come back here and defeat the first demon wall. for the second demon wall, i don't think it's impossible for you to beat it. try casting slow onto it. sure, it might causes miss hits but keep trying and chances are, u might get the demon wall in the slow status. gud luck!

Answer 2

There are two walls.
the first one you can just run away (recommended if your character has low level -below 20).
Either way, though, your characters should at least be around level 18, or you will have a very hard time beating that nasty creature. Level up at another dungeon until you reached level 18 or more.

-I believe I have reached level 26 by then. I just bombarded the wall easily. I beat both of the walls in one go.

The 2nd Demon Wall is slightly weaker than the first one.
As you might notice, time is ESSENTIAL in this battle.
At the start of the battle RUN toward the boss like hell and start attacking it with your best hitter party. Arrange this in your characters gambits (Ally any->Alarm Clock, Ally Any->Eye drops/Blindna).

If you have unlocked Quickening (You should by now), UNLEASH it ASAP. Consider turning off Cure gambit as it slows down your party. Instead heal manually with Hi potions.

Don't wait too long as the Demon Wall has an ability that can BANISH YOUR party (you can't bring them back unless if you move to a different area).

Consider using ethers to regain MP of the character that has Quickening. and UNLEASH the QUICKENING again.

Another way (KINDA RISKY)
is to touch a torch among the railing. if you are lucky, the flame will extingushed and the Demon Wall will STOP for a few second.
If the flame truns blue, however, The Demon Wall will SPEED UP.
I heard there are more halt torches than speed up torches.. so try it if you are desperate.