The Royal Paladin (ロイヤルパラディン) is a clan from the United Sanctuary nation. They have a variety of effects, including Soul Charging, boosting power, and Riding/Calling from the deck but have a main focus that is gaining strength in numbers.
Aichi Sendou uses this clan both in the manga as in the first season of anime, until he started to use Shadow Paladin deck while he is under the influence of PSY Qualia and completely abandons Royal Paladin unwillingly for a Gold Paladin deck instead in the second season. Kourin also uses a Royal Paladin deck in few episodes. The Royal Paladin was sealed in second season along with Shadow Paladin and Kagerou (Cardfight!!).