Creed Diskenth (Black Cat) fused with Imagine Blade Level 3.
After his final Hōgyoku transformation, Sōsuke Aizen's (Bleach) right hand fused with his Zanpakutō, Kyōka Suigetsu.
Ichigo Kurosaki (Bleach) fused with Tensa Zangetsu.
Baishin (Bleach) fused with his Zanpakutō.
After Awakening, Priscilla (Claymore) assimilated her claymore into her own body.
Dante (Devil May Cry series) in an attempt to confirm his guess about Rebellion's hidden power, stabbed himself with his sword resulting in fusing with both it and his father's sword, Sparada awakening his Sin Devil Trigger…
…but manifest a new sword from his very being, Devil Sword Dante, which far surpasses either blade.
Nizō Okada (Gintama) fused with Benizakura.
Gintoki Sakata (Gintama) fusing with Lake Toya.
Tōshū (InuYasha) fused with Dakki.
InuYasha (InuYasha) fused with Sō'unga.
Nico Minoru (Marvel Comics) is merged with the Staff of One, which emerges from her body whenever her blood is shed.
Kisame Hoshigaki (Naruto) fused with Samehada.
Wapol (One Piece) fused with an entire armory.
Saga (One Piece) fused with Shichiseiken.
Ruber (Quest for Camelot) uses a special potion to merge human beings with weapons...
...doing so with himself and Excalibur to ensure no one would ever take it from him.
After 10 years of fighting against dragons, future Ragna (Ragna Crimson) merged with his silver sword.
A samurai (Yu-Gi-Oh!) equipped with Fusion Blade Murasame Blade.
Cyber Blader (Yu-Gi-Oh!) equipped with Fusion Weapon.
Rubilax (Wakfu) like all Shushu can fuse with their Wielders.
Tatsumi (Akame ga Kill) fully bonded with the Demon Armour: Incursio.
By merging with his revolver, Vash the Stampede (Trigun) can form his Angel Arm.
After his transformation into a one-eyed ghoul, Koutarou Amon's (Tokyo Ghoul) quinque, Doujima 1/2, merged with him, becoming a kagune he could bring forth to replicate it.
Zero Kiryu (Vampire Knight) merged with his anti-vampire handgun, Bloody Rose.
Nero (Devil May Cry) merged the Yamato into his Devil Bringer, allowing him to manifest its power in his Devil Trigger.
Canis Lykaon (Slash Dog) one of the Thirteen Longinus was born from the irregular fusion of King Lykaon who was transformed into a werewolf by Zeus and Ame-no-Ohabari, the most powerful divine blade of Shintoism imbued with the flames of Hinokagutsuchi…
…being the host of Canis Lykaon, Tobio is linked to Ame-no-Ohabari and can also summon the sword from within himself.
Crona's (Soul Eater) Demon Weapon, Ragnarok, was melted down into Black Blood and bonded to him.