The user is capable of enhancing the performance of any weapon by supernatural or scientific means in order to make them stronger and give the new and/or greater powers. The weapon may have added material to make it less fragile and more durable, or enhanced features to make them more powerful.
May need to have rare items or spells for an upgrade
May be heavier than previous version of weapon.
Takes time to get used to weapon.
May lose advantage of previous weapon before upgrade (ex. new gun has more power and range, but has less ammo and accuracy than previous one).
May not be downgraded again.
May be stolen by enemies and used against you.
Refined Weapon may only be used for certain people
Hermit Gunsmith (Cave Story)
Adele von Ascham/Mile (Didn't I Say to Make My Abilities Average in the Next Life?!)
Link (The Legend of Zelda series); via various weapons
Ghost Rider (Marvel Comics); via Hellfire
Sonic the Hedgehog (Sonic the Hedgehog series); via Ancient Lights
Tim Drake/Robin (DC Comics)
Bunnie D'Coolette (Archie's Sonic the Hedgehog); via robotic limbs
Mario (Super Mario Bros.); via Hammer
Luigi (Super Mario Bros.); via Hammer
Nami (One Piece); via Clima-Tact
Usopp (One Piece); via Kabuto
Brook (One Piece); via Soul Solid
Franky (One Piece); via Vegapunk's technology
Sango (InuYasha); via Boomerang
Samus Aran (Metroid); via upgrades to her Power Suit weapons
Various RPG game characters (Final Fantasy, Breath of Fire, Legend of Dragoon etc.)
Ryu Hayabusa (Ninja Gaiden); via various weapons
Power Rangers (Power Rangers)
Sentai Rangers (Super Sentai)
X (Mega Man X); via his variable weapons system, armor, and limitless potential
Zero (Mega Man X); via his techniques, variable weapons, and black armor.
Edward Elric (Fullmetal Alchemist); via switching automail limbs with a cold climate model (manga/second anime)
Buccaneer (Fullmetal Alchemist); via switching automail arm with different types
Xenovia (Highschool DxD); via Ex-Durandal
Malga Naruse (Horizon In The Middle of Nowhere); via Weiss Fräulein
Margot Naito (Horizon In The Middle of Nowhere); via Schwarz Fräulein
All Zanpakutō users (Bleach); via transformation of Zanpakutō into Shikai and then Bankai form
Dante (Devil May Cry); via devil arms
Jax (Mortal Kombat); via Cybernetic Arms
Haru Glory (Rave Master); via Ten Commandments
Pit (Kid Icarus); via Bow upgrades
Jak (Jak series); via Morph Gun upgrades
Hammerhead Bros (Mario & Luigi: Superstar Saga)
Matt Murdock/Daredevil (Marvel Comics); via improvements to his Billy Club
Peter Parker/Spider-Man (Marvel Comics); via modifications to his web formula for special situations.
Steve Rogers/Captain America (Marvel Comics); via enhancements to his shield
Misty Knight (Marvel Comics); via bionic arm
Tony Stark/Iron Man (Marvel Comics)
Forge (Marvel Comics)
Marc Spector/Moon Knight (Marvel Comics); via Truncheron
Chuck Greene (Dead Rising)
Frank West (Dead Rising)
Kankuro (Naruto); via Sasori Puppet
Sora (Naruto: Shippuden); via Chakra Enhanced Triple-Bladed Claw
Haru Glory (Rave Master); via reforging of his Ten Commandment sword by Musica to unlock its final form.
Angeloids (Sora no Otoshimono); via Pandora
Nightmare (Soul Series); via Soul Edge
Satsuki (Starbiter Satsuki)
Lion-O (ThunderCats 2011); via Sword and Gauntlet of Omens
Slim Cognito (Ratchet & Clank Series)
Many Power Ranger characters (Power Rangers Series)
Many Super Sentai characters (Super Sentai franchise)
Weisz Steiner (Edens Zero); via Ether Gear
The Travelers Sword (Brave Story); via goddess stones
The Pack-a-Punch (Call of Duty series)
The Onikiri/Kien (Darkstalkers)
The Light Capsules (Mega Man X series)
The Nanotech (Ratchet & Clank Series)
Various Weapon' Vendors (Ratchet & Clank Series)
The Dispersion Pistol Powerup (Unreal Series)
The Batour (Wild Arms: Twilight Venom)
In order to survive a disease, Bunnie D'Coolette (Sonic SatAM/Archie's Sonic the Hedgehog) must have her robotic limbs upgraded with a cooler design.
Whenever his regular formula for his web-fluid is not enough, Peter Parker/Spider-Man (Marvel) can create different versions of his formula for dealing with the situation, such as a type that can resist fire....
...and a magnetic variant that blocks radio frequencies.
Moon Knight (Marvel Comics) upgraded his trademark weapon, the Truncheron
After it was destroy by the Serpent, Tony Stark (Marvel Comics) used Uru an Asgardian metal, to repair the shield of Captain America and made it stronger than ever.
The Sword of Omens (ThunderCats) repels Mumm-Ra when the Eye of Thundera was inserted into it
Lion-O (ThunderCats 2011) used the Spirit Stone to power up his gauntlet and added a laser beam to it.
The Pack-a-Punch (Call of Duty series) allows weapons to be upgraded to better versions of themselves, giving them attachments, increasing damage output/magazine capacity, grating added effects, and/or more reserve ammo, etc.
Frank West (Dead Rising/Dead Rising 2) can make some weapons to kill enemies more efficently
Chuck Greene (Dead Rising 2) can invent some deadly weapons so he could kill his enemies more easily
But neither Frank nor Chuck had made some crazy weapons as Nick Ramos (Dead Rising 3). His mechanical skills can turn even the most harmless toys into deadly weapons.
Jak's Morph Gun (Jak and Daxter series) is capable of being outfitted with numerous upgrades that allow it to possess several eco mods with weapons for each, as well as increased ammo capacity, damage output, and rate of fire.
Mario & Luigi (Mario & Luigi: Superstar Saga) had their hammers reforged to break harder rocks.
Mega Man X's (Marvel vs. Capcom: Infinite) X-Buster was upgraded by Iron Man into the Infinity Buster, a massive cannon powered by the Infinity Stones, in order to destroy Ultron-Sigma.
The Light Capsules (Mega Man X series) are inventions of Dr. Light that give X a part of his many armors that upgrade his abilities. Some capsules also give X a full armor, chips that enhance the power of the current armor, or a secret technique.
For example, X's (Mega Man X series) First Armor allows him to dash on the ground and in their air, increase his resistance to damage, and fire a more powerful Charge Shot.
X's Fourth Armor increase the power of his body and weaponry, and also grants him the Nova Strike ability.
In his Ultimate Armor, X possesses all of the enhancements provided by the Fourth Armor with much greater power, and can use the Nova Strike for an unlimited amont of time.
The Dragon Sword (Ninja Gaiden) can be upgraded as well being infused with the Eye of the Dragon.
Racthet (Ratchet and Clank series) is able to use the Nanomites he gathers from defeated enemies in order to upgrade the strength of his weapons.
E-102 Gamma's (Sonic the Hedgehog) upgrades include a laser blaster to lock onto more enemies and a jet booster for hovering.
The Ancient Light (Sonic Adventure series) allows the characters to posses various power-ups for certain levels.
Nightmare (Soul Calibur) wields Soul Edge which was a normal sword before bathing it in the blood of countless victims. Because of this it becomes stronger when it comes in contact with blood.It can also restore its strength with every shard of Soul Edge found.
Spyke (Splatoon) can increase the amount of sub-ability slots a piece of gear has in exchange for gold or Super Sea Snails (sitting next to him in this
The Master Sword (The Legend of Zelda series) is Link's most trusted weapon. Even in its final form, its power can be increased by smithing or magical means…
…in some cases, resulting in the Tempered Sword, and the Golden Sword, doubling and eventually quadrupling its power.