To get the extremely powerful 7th Heaven Sword you should start with the Serpent Sword, then upgrade it to the Evilcise Sword. After that upgrade it to the Drain Seeker Sword. Upgrade that to the Dark Cloud Sword. Finally you can upgrade it to the 7th Heaven Sword. The sword has a max attack power of 240, with End and Sp of 99, amd Mp of 110. It takes alot of work to get, but it's accomplished easily by going to the back levels of the dungeons.