|This article is about a/an set of alternate forms in Kamen Rider Gaim.|
- "Decade Arms: Hakaisha on the Road!"
- ―Transformation announcement[src]
Decade Arms (ディケイドアームズ Dikeido Āmuzu) is a Legend Rider Arms based on Kamen Rider Decade's default form. Accessed through the Decade Lockseed or the Heisei Rider Lockseed channeling the Decade Lockseed, this form's Arms Weapon is the Ride Booker.
- Kamen Rider Fifteen (Heisei Rider vs. Showa Rider: Kamen Rider Taisen feat. Super Sentai)
- Kamen Rider Gaim (Kamen Rider Battle: Ganbarizing)
- Kamen Rider Zangetsu (Kamen Rider Battle: Ganbarizing)
This form's Arms Weapon is the Ride Booker.
- Decade Slash (ディケイドスラッシュ Dikeido Surasshu, Decade Arms): Fifteen uses Ride Booker Sowrd mode unleashed a series of slashes against his opponents amplified by self-replication (Attack Ride: Illusion) and multiple slash abillity (Attack Ride: Slash).