The user can enhance the defensive capabilities of themselves and/or others so that they can reach high-level mastery and control instantaneously, even reach a level of power that is usually beyond their limits alone. Users cannot steal or give power, only enhance the ones their targets already have.
Ichigo Kurosaki's (Bleach) using Blut Vene to compress spiritual pressure into his bloodstream, drastically increasing his defensive powers and sealing wounds shut.
Using his Ki, Son Goku (Dragon Ball series) enhances his defensive abilities to the extent that he can block sword attacks with one finger.
Using his Ultimate Shield, Greed (Fullmetal Alchemist) hardens his skin into carbon, enhancing his defenses.
Using Telekinesis, Sylar (Heroes) enhances his defensive ability to survive being shot.
John Smith (Hitman Agent 47) has subdermal body amour which can protect his body against knives and even gunfire.
Danny Rand (Iron Fist) can focus his chi to generate an "aura" to protect himself from energy-based attacks to a varying degree, and make himself more resilient against physical damage
Using Reduce Damage, Cole MacGrath (Infamous) permanently augments his defensive capability.
5-U-93-R (Injustice: Gods Among Us) is a Kryptonian nanotech drug that increases the user's durability to superhuman levels.
When he had his Telekinesis, Nathan Summers/Cable's (Marvel Comics) could use TK fields to deflect projectiles...
...and slow down there inertia.
Steven Armstrong (Metal Gear Rising Revengeance) has nanotech infusion, which causes his skin to harden different parts of his skin in response to physical trauma while also giving him immense strength
Eijiro Kirishima's Quirk (My Hero Academia) allows him to harden his skin for defense and attack
Using Busoshoku/Armament Haki, Monkey D. Luffy (One Piece) can increase his defensive power.
Vergo (One Piece) can coat his whole body in Busoshoku/Armament Haki to drastically increasing his offense and defense.
Trafalgar D. Water Law (One Piece) using Busoshoku/Armament Haki to defend himself against Doflamingo's Five String of Color.
Roronoa Zoro (One Piece) specializes in Busoshoku/Armament Haki to protect his katanas from damage and increase their cutting power
Sanji (One Piece) uses Busoshoku/Armament Haki to protect his legs from attacks as well as increase the power of his kicks.
Pica (One Piece) can coat his whole body in Busoshoku/Armament Haki to drastically increasing his offense and defense.
Jinbe (One Piece) uses Busoshoku/Armament Haki to protect his arms from bladed attacks as well as to increase the power of his arms.
Charlotte Katakuri (One Piece) can enhance his Busoshoku/Armament Haki to extreme levels in conjunction with his Mochi Mochi no Mi which makes it a lot stronger than regular Haki-enhanced armor.
Users of Force Barrier (Star Wars), like Luke Skywalker, can create an invisible force field that can repel blaster fire...
...or falling debris.
The Battalion’s Backup (Team Fortress 2) augmentative field augment the defense of anyone within the field.
Using his Iwagakure Ninpo, Gabimaru (Hell’s Paradise: Jigokuraku) can boost his body with defensive, harden effects.
The Regulus Nemea (Highschool DxD) has the secondary ability to protect its wielder from projectile weapons and attacks.