The Story of Valorant
The Story of Valorant is very cryptic, but it does exist. By playing Valorant, you are in fact taking part in a fight between two factions for the control of Radianite, a substance with very specific properties.
We know very little about the Agent's past and that of their world. The developers have fun sneaking clues here and there about what happened to Earth a few years ago and why the Agents fight to death.
To learn more, you have to observe every corner of Valorant, from its maps to its Battle Pass. The developers have promised that the story will be more developed from Chapter 2. In the meantime, we take stock of everything we know or guess about the lore of Valorant.
First Light, the beginning
A few years ago, a mysterious phenomenon disrupted the balance of the entire planet. No corner of the earth has been spared by what has been called the First Light. This cataclysmic event deeply impacted Life as we know it. It was also the source of a sudden technological revolution and an imbalance of geopolitical forces.

The exact nature of the First Light is unknown. We don't know either its origin or its real impact on the world. The events of Valorant unfold long after, when the face of the planet has already been changed. All we can do is see what has changed about our world.
The training range and Ascent show real changes in the laws of physics, gravity and time. However, it's not known whether this is a direct consequence of First Light or the technologies associated with it. This corner of Italy seems, for the moment, to be the only one to have undergone such transformations.
The Radianite
In all likelihood, the First Light is at the origin of the appearance of Radianite on Earth. All the properties of this substance are still unknown, but it seems to have effects on organic matter as well as on mechanics.

Radianite acts as a catalyst in human beings and reveals unsuspected skills for some of them. They then discover powers, such as that of manipulating fire, stealing or healing. Each human being responds to Radianite differently, but those who exude powers from it are called Radiation.
New technologies, and therefore new weapons, have been developed thanks to Radianite. It's used in most of the Valorant Agents equipment.
Kingdom
Following the appearance of Radianite, a company specialised in its study in order to use its different properties: Kingdom. It's likely to be a multinational corporation that is equally specialised in very high technology and pharmacology. They use Radianite on human subjects to determine its effects on living things and to create Radiants at will. These Radiants then become soldiers who defend Kingdom's interests.

Even if we don't know what Kingdom's end goal is, we already know that it's looking to collect the biggest stocks of Radianite in the world, and that isn't a good idea. The Valorant Protocol was created to stop Kingdom.
All of Valorant maps represent important Kingdom bases.
Split is nothing less than the company's headquarters in Japan. Kingdom has taken over the entire Shibuya district, if the overexposure of its logo on the walls and in the streets is to be believed. It's mainly an administrative headquarters, we don't know what is developed there.

Bind is a zone in Morocco that Kingdom has appropriated to refine Radianite there. The Spike was made in Bind's labs (which is why Kingdom's K can be seen on every Spike). It's not known why Kingdom needed to create a Spike, the only device capable of destroying Radianite. Perhaps they are using it to destroy evidence, to destroy their opponents' reserves, or to generate attacks.

Haven is a temple in Bhutan abandoned by its inhabitants after being disfigured by First Light. It centralises the Radianite reserves of South Asia. This is obviously just a storehouse of Radianite.

Ascent is a piece of Italy suspended in time and space. An explosion, probably related to Radianite, threw a large portion of the Earth into the sky. We see what appear to be rifts in reality. These flying islands are owned by Kingdom, according to documents hidden on Bind, as well as various promotional signs found on Bind and Split.

Finally, Icebox is a centre for the study of Radianite located in the frozen wastes of Russia. It's unclear what Kingdom is doing there, but it's obviously a mining site, in addition to being a warehouse for Radianite. There are numerous tanks containing traditional Japanese armour bathed in Radianite, visibly dug from the wreckage of a ship.

Valorant Protocol
As the events of Valorant unfold, Kingdom dominates the planet with its technology and Radianite reserves. There is only one tiny hope left to stop them: the Valorant Protocol.
Valorant Protocol is a large-scale mission, carried out by a secret organisation. It's not known who is behind this organisation, but it appears to be the result of an international alliance between different states, unable to stop Kingdom by legal means.

Members who work for the Valorant Protocol are called Agents. Since Kingdom uses Radiants to carry out its missions and protect its interests, the Valorant Protocol also calls on these enhanced humans.
One of the Agent's first missions made them able to appropriate one of Kingdom's flying islands. This is the training range, where Valorant Protocol members hide and train, while awaiting their missions.
Each game of Valorant actually represents an attack by the Protocol Agents on Kingdom. Unlike Counter-Strike where the heroes try to stop terrorists, it's the heroes who try to blow up enemy facilities.
The Agents
In Valorant, all playable characters are referred to as Agents, whether they work for the Valorant Protocol or for Kingdom. It's not clear which camp each of the Agent is operating in.
It's important to note that an Agent is not necessarily a Radiant. There are actually only 6 Radiant playable in Valorant so far.

Jett is a Radiant capable of handling the winds. Phoenix is a Radiant capable of generating fire. Omen manipulates light (and by extension, shadows). Reyna and Sage can manipulate the life energy of living things. Reyna prefers to absorb it to become more powerful, while Sage prefers to use it to heal her allies. Skye also appears to be able to manipulate life energy, but she uses it to give shape to spirits.
The other Agents are not Radiants, but they use Radianite infused equipment. Breach's arms, for example, work with Radianite, just like the gadgets of Killjoy, Cypher, Sova and Raze. In the case of Brimstone and Viper, they use conventional technologies, but coupled with Radianite to increase their devastating effects.