Dear all
I can't beat the Doorlord and he can kill the party with a 9999 attack to all
Any tips?

If you're talking about the Doorlord guarding the entrance to the MysTech Tunnels, you're not supposed to fight him; there's an alternate entrance into the tunnels. If you mean the one INSIDE the tunnels, that fight is purely optional and yields the best shieldcell in the game, although there are plenty other shieldcells that will do the job well. If you're intent on killing him, however, then use stunning attacks so that he can't get this turn. It's very difficult, but it can be done.

What Charon121 said, basically.

It's definitely the hardest fight in the entire game.

On my first playthrough I intended on fighting him close to the end, but by then I'd forgotten about him.

Thanks, yes, the second encounter. But' I've already solved!