OK, the key for the Liches room (door by the bridge) you have to get wet to obtain. Jump off the bridge and take the right tunnel cut into the wall. Follow that through and I believe that you have to take the nothernmost opening to get to the key room. After the current pushes you through, you will find yourself in a room with the key. Grab the key and work your way back up to the door. I'm not sure which door you mean by the "one in the library". It's been awhile since I've been through skull castle and my memory is foggy. The rod of death opens the door to Madda Mabbig, which is in the basement up the stairs from the pool of water. Use the rod on the lock, and it will open.

Serath
"Less talk, more fight!"

Just to expand on the previous message, Madda Mabbig's chamber is in the west dungeon area across the hanging bridge.

Serath
"Behold Boo's fury! It's tiny, so look close. Trust me, It's there."

Well I don't have the key for the vault so I know I can't go that way, they're are only two other doors I haven't been through, one in the library, on one in the hallway near bridge. I have the rod of death but can't seem to find the door I'm supposed to use it on, and I explored every inch of the place many times the two doors without locks don't open. another thing I was wondering is that evil doll thing near library am I suppossed to do something there?

Not the door near bridge I meant , I already got into the library which is the door I think you mean. The two doors besides the vault key one I mentioned don't have lock to use keys on. I already been to all 4 water path many many times and everywhere else. there is one switch that is non-functional...Well thanks for trying ut I'm going to give up on this "Item Hunt" game and play an RPG instead.