The Ultimate Dream Katana is one of the best AoE melee weapons in game. It is the upgraded version of the Electronic Katana. It's massive +4200 melee strength bonus allows it to tear through enemies in its attacks radius. It is very popular, due to the lack of AoE alternatives in a similar price range.
You have the chance to upgrade your Electronic Katana into an Ultimate Dream Katana at ::upgrade. The upgrade is rated at a medium difficulty.