Can I get both the Elden Phalanx Kalia Scepter and Full Moon Magic at the same time?

No. According to the official website of the game, you can't get the Scepter of Kalia and Full Moon Magic at the same time. You can only choose one of the two, "Elden Falcon" is a dark fantasy world as the stage of the action RPG game, is everyone commonly known as the soul of the game action adventure game.