Necropolis is not a castle. There is a Necropolis castle ;). I agree that the concept of a "Necropolis race" is not entirely appropriate, but it implies a "race of undead," i.e., a "race of the dead." Does that make sense? And the dead are no worse than demons, humans, or elves :).
Цикл "Закадычные враги": "Особенное гостеприимство, "Супероружие", "Меж молотом и наковальней"
"Падение Шантири"
Кампания для "Кодекса Войны"
"Выбор Сагиттеля"