Mahou Shoujo Miracle Aro wa no Otouto

Meet Aroha, the older sister of Karua—a middle school boy who loves video games— who came into his life when his parents remarried. But her true identity is... Magical Girl Miracle Aroha!? Alongside David—a mascot character who seems cute but really isn’t— Karua provides brilliant support to this hopeless magical girl (who thinks no one has figured her out yet), all while making sure no one notices him!!