Berserker is an enemy in Kingdom Hearts II and first appears in Twilight Town when Sora attempts to meet Kairi.
Berserkers are very bulky and wield giant hammers used to attack and defend. They are the biggest lesser nobodies and are one of the more powerful.
Strategy
Berserkers are very strong and have an equally strong defense. Moving in for a head on attack can be risky. A good way to deal with them is to come in close an reflect his attacks waiting for his Reaction command to show up. Using it will greatly diminish the Berserkers health as well as any other Nobodies that you capture with it. A good alternative is using thunder or blizzard at a distance to help preserve HP or using magnet followed by a limit or Thunder to finish the Job.