I was on level 55 when I beat them, and it still took a ton of tries to work it out. The
trick is that Alice will heal either one of them constantly if their hit points get too
low. Her electricity attack is hell, so always keep running- you can run as fast, if not
faster, than either of them- but only if you know how to dodge well! Mostly, just spam the
attacks on Alice, and as soon as she starts casting, immediately interrupt it or you'll
never win. I bet I used Devil's Fire about twelve times during that battle just to get
them both, so don't be stingy with the healing items or the artes. In my opinion, this is
actually harder than the final battle against Richter, so go all out. Once she's down,
Decus is a piece of cake. Just watch out for both of their divine artes! They usually
won't kill you, but they'll bring you down to 1 hit point, no matter how strong you are at
the time. So be ready with the healing items after they've done their thing.

Hope that helped. Mostly, just level up a LOT. :)

i was a level 79 when i beat them i lost 57 times. here is the trick use marta in the back
to use revive and healing spells ok.you follo,good.decus will try to kill marta mostly so
try to keep her alive. use devil's fire to kill ALICE first she will use ground = dasher
on emil all the time and use first aid on decus so kill alice first and keep decus away
from marta.try this and you will win easy. after you fight richter though you will fight
yourself. just let marta and lloyd kill you for a happy ending here.gamers rule!

lvl 55 and up will do just make sure you have a lot of gels and life bottles also you
should beat Alice first and put one off your beast on atk same and the other on protect
friend because Marta is gonna get hit a lot and last dont get to close to Decus he hits
really hard

Emil was 58 and Marta was 57 and i fought them playing as marta the second playthrough and
i beat them in one try. what really helps is to have good monsters in your party (i had a
lvl 55 Sword Dancer and a lvl 25 Were dragon [was trying to make him into another dragon,
was blade rex])also instead of using emils devil's hellfire, use Marta's Radiant Roar.
Radiant Roar its alot better then devils hellfire because it has a large area it hits, it
does more damage, and it also heals your allies. so whenever your unison gauge is full,
you can wait till your allies hp is low or use it whenever you want but just start to cast
a high magic arte (i always use divine sabre) and hold don B for the Mystic Arte

Yea I was actually basically the same level as you. If you have any manuscripts to use on
yur monsters who are low leveled do that and basically what I did was whenever Marta's
health was 1200 or below I used a lemon gel and whenever Emil's was 2000 or below I used
one. Whenever Alice uses a spell use a unison attack and go for her first. Then Decus just
make sure you have plenty of items cuz he does a lot of damage. Using an all divide there
should help becuz he doesn't hit many times.