Become Your Weapon

Why bother putting yourself through the troubles of undergoing a typical One-Winged Angel? It's too damn messy, too damn long, too damn late, and it makes you look so damn ugly that it guarantees your death. Hell, your One-Winged Angel might even be clipped as you're performing it, leaving you as an even better target.

However, you can't undergo a One-Winged Angel that completely annihilates your enemies - that's too dull. Such an exaggeration of your Badassitude almost always tarnishes your reputation. So, how can you fight your opponents adequately, enough that you're not as likely to lose, but enough that you're not going to win automatically? Find an Empathic Weapon (or make one), and merge with it. You get a boost in power, likely enough to hold your own against your enemies, and your margin of error is about equal to that of the heroes' - it can go either way.

Sub-Trope of One-Winged Angel. Contrast Fusion Dance. Also contrast Natural Weapon (the weapon is already part of your normal anatomy) and Equippable Ally (when something or someone else becomes your weapon).

Examples of Become Your Weapon include:

In Bleach this can be found in the Arrancars, an evolved race of Hollows. Unlike the Shinigami, an Arrancars' Zanpakuto is their Hollow form sealed within a weapon, and it isn't sentient. Activating their Zanpakuto is called Resurrección, allowing for a near-complete restoration of their former Hollow selves. This is a subversion - in typical One-Winged Angel fashion, their defeats tend to be green-lit when they transform.
- Again from Bleach, during the Bakkoto arc. One of the assassins, Jinnai Doko, literally eats parts of his scythe/Bakkoto Retsurai and turns into a monster with the skin made of blades.
- Another one from Bleach. Toward the end of the Bount arc, Yoshino Soma fuses with her Doll Goethe, transforming into a humanoid fire elemental made out of flames and magma. Both entities are still present, but Yoshino is the dominant character in the merger, reflected in their hybrid having a distinctly female figure.
- Final example (we swear) - when Ichigo merges with Zangetsu and his inner hollow, to perform Mugetsu.
Naruto had Kisame Hoshigaki fuse with Samehada, his Empathic Weapon.
- In a Naruto filler arc, the Big Bad merges himself with the various weapons of all his now deceased underlings, resulting in a living armor shell with blades and energy dragons coming out of it.
The Unison Devices in the Lyrical Nanoha franchise are tiny sentient humanoids who exist specifically to physically merge with their masters and give them enormous power boosts. The only downside is that very few mages can handle Unison.
Quest for Camelot: Ruber uses a potion that causes this on his army.
Wapol from One Piece can merge himself with a weapon after eating said weapon. This can result in him having cannons in lieu of hands and tongue. He also tries to go over the top by devouring the whole armory of his castle, but thankfully Nami stole the key from him in time.
Valon in the Waking the Dragons arc in Yu-Gi-Oh! uses Armor monsters, which do act something like this, given that 1) the Orichalcos power makes them real, and 2) he actually wears them, allowing the player to actually take part in the active destruction of other monsters.
In Final Fantasy XII, the final battle against Vayne Solidor is broken into three separate battles. In the last battle, he fuses with the rogue Occurian Venat (one of the gods) to form The Undying, which serves as the final boss.
In Pathfinder, a high-level summoner has the ability to merge forms with his/her eidolon, combining their stats and effectively acting and fighting as one being.
- The Synthesist archetype allows them to do it from level 1, at the cost of not being able to summon the eidolon as a separate being.
At the end of Atelier Iris 2: The Azoth of Destiny, Palaxius pulls this trope when he merges with the Azoth for the final boss fight.
This is present in Skyward Sword; Demise uses Ghirahim as his weapon in the final battle.
In Power Rangers Operation Overdrive, the Sentinel Knight merges with the sword Exelsior, giving him a physical form once more; he's then able to go from humanoid to sword and back at will. After some adjustments by the team's TV Genius, he also merges with Mack the Red Ranger to give him his Super Mode.