The Tomb Of The Unknown King
When you find The Tomb Of The Unknown King and find the ID No. of the person they asked for don't leave the cave yet. You probably missed a GF named Brothers! What you do is first go to point A on the map and defeat the mini-boss there.Note-Buy a map from the man that asks for the ID No. and a battle meter too. This will make your trip much easier when you go through the cave.
Next go to point B and release the water into the tomb by pressing the switch as shown in the picture. If you don't do this then you can't finish the cave and get the GF Brothers.
Next you must go to point C on the map and take out the switch or gear that is there. After this you can complete the process by going to point D and defeating the GF. Be sure to save before fighting them. You should draw from them since you can get some pretty good magics for the time from them. After you defeat them you will get a card. To get the other just open the coffin in front of you.
Note-A good way to kill them faster is to cast float on them since it says if you scan them that they recover hit points if their feet stay on the ground.