Silver Fang, privately known as Bang, is one of the most overpowered members of the Hero Association. Unlike many of his comrades, he is vociferously for the cause of justice, not to mention completely ignorant (and unheedful) of the prestige and privilege that comes with his job. He wants nothing more than to fight evil, and he does so in spectacular fashion.
Given his importance in the One-Punch Man narrative, it's obvious that Silver Fang is blessed with a plethora of powers and abilities, the most powerful of which is his brand of martial artistry — the Water Stream Rock Smashing Fist. Obviously, this particular old man is capable of a lot more things, some of which are subsets of his main style. (Minor webcomic spoilers present)
10 He Is Referred To As The "Greatest Treasure Of Martial Arts"
Although this isn't technically an ability, being known as the Bujutsu-kai no shiho, or the "greatest treasure of martial arts," implies that Silver Fang is one of the most skilled and astute warriors on Earth.
He has held this informal title for several years and is also believed to be one of the two backbones of the hero community (with Superalloy Darkshine). The main reason for these praises, however, is for the development of a highly refined form of combat, an iconic sign of his experience.
9 His Attacks Can Generate Craters
Silver Fang is not the third-ranked S-Class hero for no reason. When an enormous meteor threatens to decimate Japan (and probably half the world), Saitama shatters it in a single punch, but the old man continues shattering the remnants of the space object.
Bang's physical strength is such that when he battles his own rogue student, his attacks leave an enormous crater in the ground, and Garou is left both awestruck and severely injured.
8 His Four-Pronged Ryusui Gansai-ken
The Water Stream Rock Smashing Fist, or Ryusui Gansai-ken, is called "the perfect blend of offense and defense" according to Genos. There are four forms to this art.
The Ryusui-jin, which employs unarmed combat in a designated space; the Gasoshi, which uses individual pinpoint attacks to great effect; the Shunshinko, which incorporates movement (as if like fluid water); and the Mikiri, which permits Silver Fang to negate his internal limits, thereby amplifying his overall prowess.
7 He Is As Fast (If Not Faster) Than Atomic Samurai
Being fast is one thing, but Bang's aptitude for speed possibly exceeds that of his colleague, Atomic Samurai, who is himself famed for the incomprehensible velocity of his swordsmanship.
After Saitama destroys Boros, the latter's spaceship begins to collapse, and the old man is the first person to get out of the area, speeding ahead of everyone else (who aren't able to fly). Similarly, Silver Fang is capable of saving Genos at the last second, preventing him from being squashed by Elder Centipede.
6 His Senpu Ryusui: Goki Kuretsu-ken Is Limited
Senpu Ryusui: Goki Kuretsu-ken sounds a lot cooler in English: namely, "Roaring Aura Sky Tearing Fist." This technique requires his brother, Bomb, to perform his special style at the exact same time, producing massive internal reverberations inside the villain's anatomy.
It's more than sufficient to destroy the shell of creatures like the Elder Centipede. Unfortunately, neither of the siblings have the capacity to repeat this ability in the same fight, a limitation that is a result of being too old.
5 His Body Size Changes
For the most part, Bang resembles a stern old man with an average body (and below-average height). However, his true form is only revealed when he pushes himself to battle at the very periphery of his limits.
For example, as Silver Fang readies himself to take on Elder Centipede, his musculature visibly enlarges to the point at which his veins begin to pop out as well. This only goes to show that Bang is not one to be trifled with, and certainly not based on appearance.
4 He Possesses A "Sixth Sense"
Due to the intense nature of his training, as well as the consistency and focus involved in his martial style, Silver Fang's perceptivity exceeds most other people's (and several powerful heroes) by a large margin.
This so-called sixth sense amplifies his awareness enormously and allows him to perceive the vicinity and location of his opponents. Interestingly, this means that Bang doesn't really need to use sight, sound, or smell in order to fight, although lacking those senses would probably put a damper on his powers.
3 His Skin Is Ultra-Resilient
Bang's skin is rather durable, even though he technically has a human body. He is able to handle violent punches with barely a scratch on him, regardless of how many buildings he is thrown through.
For comparison, Atomic Samurai's disciple, Iaian, loses an arm to an identical blow. Most impressively, though, is the fact that the gastric acid generated by Elder Centipede may have short-circuited poor Genos, but Silver Fang comes out with few injuries if any.
2 He Has Unparalleled Stamina
Bang is an 81-year-old man, so one can safely assume that he is nowhere near the level he once was during his prime. Still, there is no stopping this ancient martial artist, as he claims that he can sprint tens of miles before he starts feeling out of breath.
In fact, it is this very stamina that permits him to perform such feats as manipulating and diverting the electricity bolts flashed at him by Orochi, the Monster King.
1 He Can One Punch Too
Sure, Silver Fang is not as strong as Saitama (he admits this himself while chastising Charanko for insulting him). He will never be able to finish off the likes of Boros or Orochi with a single punch, but he has shown several times that he doesn't need any more than that to kill Dragon-level threats.
In the webcomic, Bang rescues Genos from Fuhrer Ugly and Gums, two minions of Psykos, before ending both of them before the Cyborg can even blink (if he even blinks, that is). As Bomb says, "When Bang gets serious, it's quite a spectacle!"