Fusion Gear

Fusion Gears are a special form of Sacred Gear in Highschool DxD: Blazing Dusk and Midnight Dawn. They are made when two Sacred Gears or a Sacred Gear & another similar item (Such as a Holy Sword) are fused.

Summary
The first Fusion Gear was formed when past users of the Boosted Gear and Divine Dividing had to combine their power to keep Trihexa sealed away. This resulted in the temporary creation of the Dragon God's Blade, a sword with the power of both Sacred Gears.

Most Fusion Gears can only be made through a very long and difficult ritual in which the owners of the Gears willingly release them and manipulate their energy to come together, causing the Gears to fuse. The resulting Fusion Gear can be used by both participants, and its power level is equivalent to the product of the two reactant Gears when they are multiplied together (example: let's say Divine Dividing & Boosted Gear both have a power level of 50. 50 x 50 = 2500. The Dragon God's Blade has a power level of 2500). The process can be completed solo by one person who has multiple Sacred Gears. It can also happen instantaneously if the Gear possessor's power goes far above its normal limit with both Sacred Gears active. The Fusion can be taken apart at any time.

Fused Balance Breaker
Activating the Fused Balance Breaker requires both users to activate it at once. It triggers a Balance Breaker that resembles a combination of those of the two Sacred Gears.

Omega Drive
The Dragon God's Blade's version of a Juggernaut Drive. Its power dwarfs even gods, due to its nature as being created for the sole purpose of keeping Trihexa at bay long enough for its seal to be fixed.

Known Fusion Gears

 * Phoenix's Talon: Created from the fusion of the Gauntlet of Balance and Boosted Gear (copy). Wielder(s): Zach Praktum. Only one user due to him possessing both of the reactant Gears.
 * Dragon God's Blade: Created from the fusion of the Boosted Gear and Divine Dividing. Wielder(s): Unnamed past possessors of the Boosted Gear & Divine Dividing.
 * Satanic Reflection (temporary): Created from the fusion of the Divine Mirrors and Mirror Alice. Wielder(s): Michael Eon and Tsubaki Shinra.

Trivia

 * The idea for Fusion Gears came to me after watching a fusion scene from the Dragon Ball series.
 * Fusing the Divine Mirrors with Mirror Alice left Michael with a strong craving for tea for a week straight, as well as a love of hats for the same amount of time.