Izuna: Legend Of The Unemployed Ninja Cheats (Nintendo DS)

Once you get to the Fire God's dungeon, you can continue to upgrade your weapons without
stopping. Simply fight inside the Fire God's dungeon and find several burn-in orbs. Fill
up your weapon with Zoufuku Talismans (increases the SP capacity of your weapon; the
Zantetsu sword that ignores defense is recommended), then burn them in with the burn-in
flame. Your increased SP capacity will remain on the weapon. After that, keep filling
your sword with Rekka for attack, Mikagami for defense, Kaishin for critical hits, and
Mikiri for evasion. Keep burning them in and switching to Zoufuku for more SP, and your
sword will have very good stats by the time you finish. Make sure to keep an un-burned
Kikan talisman stuck to it, just in case you actually are defeated.