I'm having trouble with the first demon wall, if i remember correctly if you kill it instead of running away it unlocks a path that gives a great weapon.

but the thing is, it keeps wiping my group try after try.
vaan has two quickenings, fran has two, penello has one. i got maybe 15 hits with my quickenings and it still has a bit under half health.

are there any spells its weak to? or any tips to get this and the other two down?