First all you need is the elfs spell power of the valinor. which allows you to ataumattically bring a character back to life when they die. at first fight just use this spell on the elf herself, then use it on anyone else. i recomend using it on your best character only and let the others die. on eye of sauromon, use it on idrail and berethor. this way they die and come back with full health and ap. so its actually possible to beat the hardest bosses with 2 people both really low levels.