After transformation, you can activate the finisher or summon Shadow, Kamen Rider Saikou's shadow clone, which can wield him in battle. In addition, if you press the button on the buckle at the grip end of the Kougouken Saikou, Saikou's Shadow finisher is activated. Lastly, the included Kin No Buki Gin No Buki Wonder Ride Book is compatible with the DX Seiken Swordriver (sold separately). This item cost 6,820 yen and is now available.