Scripts for beginners.

BlueHeavenHero, try this:

spawn_angels = 0

function DefenderCreatureDeath()
      local boss_creatures = GetDefenderCreatures();
            if (length(boss_creatures) == 0) and stage == 1 then
                  if spawn_angels == 0 then
                              spawn_angels = 1
                              SummonCreature(DEFENDER, CREATURE_ANGEL, 250, 12, 2);
                        end
            end
end

Added 1 minute ago
HeroOfDestiny, did you add Ilfin to the reserve for the desired player?