Ripple

History
The Ripple (波紋), also known as the hamon, originally known as sendō (仙道), is an ancient form of martial arts that serve as a core element in both Phantom Blood and Battle Tendency, acting as the main power the heroes utilized. However, not everybody can utilize the Ripple, as Zeppeli states that only one in ten thousand bears the aptitude capable of utilizing the Ripple, and the main characteristic of driving the Ripple comes from the pressure one has felt through harsh situations in life. Those who are not capable will still be able to use the Ripple, but only to an insignificant extent.

The Ripple seems to have been created at the dawn of humanity with the purpose of fighting off the Pillar Men's influence on the world. This also includes the creation of minor demi-humans, known as vampires, created through the Stone Masks, and stopping them from ever achieving perfection through the Red Stone of Asia. Ripple users have built many devices and temples across the world to help them train and learn from one another.

Techniques
The Ripple is based on using the energy of the sun's rays through breathing and empowering the body with solar energy. While it can be used to destroy vampires and zombies, it can also affect non-living things. An object, while charged with the Ripple, will become more dangerous and its user can perform several techniques that can combine with the warrior's own tactics, to allow for a very flexible fighting style. Ordinary humans can also be affected by Ripple attacks, as Caesar had used his Ripple to control a woman into fighting Joseph before he had undergone the final stages of his training, and Joseph's trained Ripple would have caused an ordinary person to feel pins and needles before fainting, similar in nature to heavy exposure to the sun's rays. Cars' ripple, boasting several hundred times Joseph's power, caused Joseph's flesh to melt. The Ripple is also transferrable between users, as both Will A. Zeppeli and his grandson Caesar transferred their Ripple to the protagonists they were aiding shortly before their deaths.

Because of its versatile nature, many warriors use different weapon ranging from a scarf,  bubbles, wine, and  bolas (a pair of steel balls connected to a rope). Many of the most powerful techniques are classified as 'overdrives', and are color named (exp: Yellow Overdrive). An object that is impacted with the force of the overdrive will carry the Ripple through it, and will become lethal to the vampire's touch; this can be used to strike an enemy in another room by breaking through a wall and causing its solar energy to disintegrate the target.

Liquids conduct the Ripple especially well (and the user's Ripple shows on liquids as actual ripples), and it can even be used to increase the surface tension enough to allow the Ripple user walk on water. It was mentioned by Joseph, that objects covered in oil can conduct the Ripple much easier. Joseph was also shown to be able to cover his body in the Ripple by channeling through his own stand; it is unknown if a humanoid stand like Star Platinum, belonging to his grandson Jotaro, could also be covered in in this method.

Weaknesses
While the Hamon users can make the most simplistic of objects into lethal weapons and become themselves dangerously powerful, they are not without weaknesses. A hamon user must be able to constantly breathe, if this breathing is stopped or reduced due to injury they slowly grow weaker to the point that they can be easily defeated even by a zombie. This weakness was exploited by many vampires, the main one being Dio, who mortally injured Johnathan and in the process prevented him from using the ripple. Dio had also discovered, that removal of heat from a ripple user causes their blood to move slowly and, makes them unable to attack as rapidly and effectively as before.

Connections
By the start of Part VII: Steel Ball Run, which takes place synchronously on the timeline of the alternate universe as Part I: Phantom Blood took place in the original universe, a similar power called the 'Spin' is introduced. This technique is first seen used by Gyro Zeppeli, but is soon sought out by Johnny Joestar, who believes that the Spin will allow him to walk again.

The Ripple and the Spin are very similar, mainly in that the Spin makes use of the Steel Balls, which makes it as versatile as the Ripple, if not more so. Gyro has been able to use it to deflect a bullet with his skin, provoke muscles to do involuntary actions, and price impact of a persons body. The Spin's power derived off the Golden Rectangle, a mathematical formula which allows for an object to spin nonstop in a divine rectangle. It is possible that the Ripple has some connection to Gyro Zeppeli's Spin technique.