im stuck at the tomb of the unknown king i cant find that guys card with his number in it. i looked everywherein the place.

U'll find the number just as u enter the tomb. Just look around and u should find a sword use the action button and u get the number. I hope I helped u out.

i thought it was in one of the rooms

In the rooms u'll find the means to enter the room in the center to get eventually the Borthers GF.

Just keep on going right from the entrance and you'll never get lost. It's easier to do the GF Brothers Sidequest that way as well.

second screen on the right wall there's this thing that looks kinda like squals gunblade action button you'll get the number

i got brothers bofore i got the number.

Just go through two screens of the maze and its on the floor.