As the world keeps turning, many people have gotten complacent at the top of the food chain. They were the masters of the world and the apex predators. However, it takes all the running you can do to stay in the same place in the world. One day, people realized that a lock or key would be appear somewhere on their bodies. It was a general rule, but there were exceptions. As time moved on, it became more and more common and widespread. It became a given fact that it was here to stay and a few decades later, 1% of humans had a lock or key. It seemed that it had not proliferated more than this at this point. Whether it was a matter of it could not spread further or that a problem occurred in the genes that prevented it from appearing in most people, was still debated by the most educated academic minds on the subject. There was still more to discover and figure out. It was a new area of study after all. Scientists had also observed what they could do. They found very interesting things during the testing and observations.
Some of those effected were voluntarily gathered for studies. In the authoritarian countries in the world, they were gathered up and experimented on with invasive procedures. There were even some countries, that tried to exterminate them. It was then that there were exoduses to more liberal or exploitative countries. There were general initial findings. They were:
Lock- Partners cum on penetration (female); make partners infatuated with them (male)
Key- Partners cum from being penetrated (male); control partners for a day (female)
White- Increases fertility
Black- Increases sexual appeal
Blue- Increases energy
Red- Grants powers
It was also found that powers could be subverted or even turned against them. While locks and keys were generally sex determinate, 1% of Lock holders were male and 1% Key holders were female. The homosexual relations between Locks and Keys seemed to initiate a "battle" where both marks glowed and the first to cum was rendered depowered for a day. It also had a stacking effect. It went 1 day, 2 days, 4 days, 8 days, 16 days and so on. If a male and female Lock or Key had any sexual relations, the dominant in the encounter could absorb the powers of the submissive once they cum. When a Key penetrated a Lock, they formed a firm bond where they could only gain the benefits with each other. Sex was also observed to be much more pleasurable with the partner. Sex outside the partnership was observed as only half as satisfying and fertility dropped to 10% from the 100% with the partner. It was therefore important to keep special watch over Locks to make sure that they were all protected from harm from those that would abuse them.