Madan Keys are magic keys that allows Ryukendo, Ryuguno and Ryujinno to use them to summon weapons, JuOhs or use their finishing moves to finish off an enemy.
When "Kenji" inserts the RyuKen Key into GekiRyuKen, he synchronize with GekiRyuKen to transform into Ryukendo. His Transformation call is "GekiRyu Transform!". By inserting the Final Key into GekiRyuKen, Ryukendo can performing his finishing attack. The Knuckle Key summon out the Madan Knuckle and it's finishing move is Madan Spark.
Fire Ryukendo is Ryukendo's fire-based powered-up form, activated by the Fire Key. In this form, Ryukendo can call for his personal JuuOh using the Kong Key, Fire Kong, which can turn into cannons.
Aqua Ryukendo is Ryukendo's water-based powered-up form, activated by the Aqua Key. Aqua Shark is Ryukendo's JuuOh in this form when called out using the Shark Key, which can turn into a hoverboard.
Thunder Ryukendo is Ryukendo's lightning-based powered-up form, activated by the Thunder Key. In this form Ryukendo can call forth his personal JuuOh, Thunder Eagle with the Eagle Key, which can become Ryukendo's wings to fly.
When "Fudou" inserts the RyuGun Key into GouRyuGun, he can synchronize with GouRyuGun to transform into Ryuguno. His transformation call is "GouRyu Transform!" . His Shot Key allows him to use a rapid-fire attack called "Dragon Shot" , and his Final Key activates his finishing move, Dragon Cannon , which releases a hundred of GouRyuGun's regular shots in one powerful blast. His JuuOh is Buster Wolf, which can transform into a motorcycle.
When "Koichi" inserts the RyuJin Key into ZanRyuJin, the weapon synchronizes with the Madan Ryu Core to transform him into Ryujino. Ryujino can turn ZanRyuJin from a halberd into a bow with the use of the Archery Key. His finishing move, activated by the Final Key, is RanGeki (乱撃) in Axe Mode and RanBu (乱舞) in Archery Mode. His JuuOh is a raven called Delta Shadow which can combine with RyuJinOh to give him the power of flight.