Seed of defense is a recurring item in the Dragon Quest series that permanently raises the maximum defense or resilience to whoever eats it. The amount varies from game to game. This seed can be found in treasure chests, pots, drawers and bags. It can also be stolen from or dropped by certain enemies. They cannot be bought.
Although absent from the original NES version, they can be found in the SNES and Gameboy Color remakes of Dragon Quest. Due to text limitations in the Gameboy Color Dragon Quest remake, seed of defense was changed to DEFseed.
In Dragon Quest VIII, this seed will increase the resilience by 1-2 points to the user depending on the RNG.