du machst einfach einen fehler
er heilt sich nur, wenn deine figuren in seiner reichweite sind, also musst du mit fernangriffen den rest erledigen.

Strategy: Before it starts, heal and recharge, and be sure everyone's got the
Black Charms and Luminous Mosses.

At the start of the battle, have Tatjana, Delma or Camellia cast Magic Shield/
Element Guard on everyone. This is a must, even if you don't have Black Charms.
Cast Speed Up and Heated Soul while you're at it, if you can.

The Lord of the Black Abyss has three moves. The first is to summon a Brain
Cell. The Brain Cells are pretty pathetic, really. As you kill them, the black
mist surrounding the Lord will begin to disappate, and his DEF will lower.
After you kill five of them, it'll be gone completely, but the Lord will be
able to use his third move, which recharges it fully.

His second move drains the life from everyone near him and heals him. He'll
only use it if someone's in range, so park as many characters as you can
outside it's effect area to cut down on the damage to your party. I believe
it's non-elemental.

He'll only use his third move when the black mist is fully gone. It's a really
poweful dark laser beam that he shoots straight out from him. This is the
reason you brought those Black Charms. It's Dark elemental. On an unprotected
character, it'll do about 300 damage. However, with Element Guard and a Black
Charm, it'll only do about 70. With Element Guard and a Frey's Hair Ornament,
two Black Charms or a Shadow Talisman, it'll do 1. Also, you can avoid this
attack by moving to the EXTREME left or right sides of the battlefield. I
suggest planting characters with less Dark res there if you can.

That said, your main strategy is going to involve killing 4 Brain Cells, then
smacking the Lord with everything you've got until the fifth Brain Cell shows
up, at which point you move your more vulnerable characters to the sides and
continue to wail on him as he lets his Dark Beam go. Once that's out, move away
and kill 4 more Brain Cells. Rinse and repeat. Use any and all healing
available to you when necessary. Don't bother using Special Moves and Magic on
the Lord, just attack him. He's got about 5000 HP.

An alternative to a mad charge at him is to bring two characters with good
range (usually Maru and Tatjana with a Superconductor Coil), plant everyone
on the sides of the map, kill Brain Cells as they approach, and attack the Lord
from the side, out of range of his area drain. If positioned correctly, he
won't be able to hit you with anything. Consider this if you're having trouble.