This ability means that Naomi cannot be killed by any ability. It doesn't matter if the ability's sole purpose is to kill, or if only that particular use would have otherwise been fatal. She can still be killed using natural, non-ability means, she still can become ill and she ages as normal. She can also still be hurt non-fatally using abilities. However, any ability used to try to kill her would have no effect, and also no smaller ability-induced injury could develop into a fatal condition.