local HandleMonster = function(monster)
  RunAsync(function()
    --Here you do whatever you need with the monster
  end)
end

local IsMonsterHandled = {}

while true do
  local AllMonsters = worldInfo:GetCharacters("","Evil",worldInfo,10000)
  for i=1,#AllMonsters,1 do
    if not IsMonsterHandled[AllMonsters[i]] then
      IsMonsterHandled[AllMonsters[i]] = true
      HandleMonster(AllMonsters[i])
    end
  end
  Wait(CustomEvent("OnStep"))
end