When Niklas Sundin and Johann Larsson left HammerFall the next year , Glenn LjungstrÃ m and Fredrik Larsson replaced them . When Niklas Sundin and Johan Larsson left HammerFall the following year , Glenn LjungstrÃ m ( then guitarist of In Flames ) and Fredrik Larsson ( the bassist of the former Swedish death metal band Dispatched ) replaced them .