gistfile1.rb

class Magic
  def initialize(attack_point,defense_point)
    @attack_point = attack_point
    @defense_point = defense_point
    @level = 1
  end

  def level_up
    @level += 1
  end

  def attack
    @attack_point * @level
  end

  def defense
    @defense_point * @level
  end
end

nanoha = Magic.new(10,5)
fate = Magic.new(8,4)

p nanoha.level_up
p nanoha.attack
p nanoha.defense
p fate.level_up
p fate.attack
p fate.defense
p nanoha.level_up
p nanoha.attack
p nanoha.defense
p fate.level_up
p fate.attack
p fate.defense