In the land of Ridon, everyone is born with a power crystal embedded into their right hand. The crystal guarantees their loyalty to the kingdom (like brainwashing them to be loyal) and grants them inhuman strength, speed, or intelligence(only one of the three). The royal family is the only one that can possess more than one power.
At the age of 3, all the children in the kingdom are tested to see which and how many abilities they possess. In the rare case that one of them does not have an ability, their crystals are removed and they are banished from the kingdom. If anyone of them somehow survives and makes it back, they will be killed on sight. This will happened even if the child is from the royal family.
What will happen if the child is not from the royal family and has more than one power? Well, the chance of that is very rare, only one in a billion. Many think that this is not possible at all.
Well, they were proven wrong when he was born. Who is he? An orphan that has no background to speak of. A nobody. Yet with luck or misfortune, he was born with all three powers. The day after he was tested, the royal family came for him. Everyone thought that he would instantly be killed. But surprisingly he was not. Instead, he was given a chance to serve the royal family and become the bodyguard of the newly born princess. In return, they would nurture and train him.
Of course, he agrees.
When living in the castle he comes upon a dungeon. It was only one occupant. They called him the Immortal Prisoner(it was the best I could come up with). Judging from the name you can already see that he is immortal but he is doomed to spend his life in prison forever.
The immortal takes an interest in the boy and trains him secretly out of boredom.
On the other hand, while getting stronger he has to protect the princess. You would think that the princess is really beautiful and has astounding talent. But it is exactly the opposite.
The princess has average looks and has no magical power at all. That's right, no magic. She should have been banished. Luckily for her, her father conducted her test in private and no one found out. So for now, people think that she has superior intelligence since that is the easiest to hide.
To make up for this, she is constantly in the library, learning new things so that people believe that she is actually smart.
The only people who know that she has no power is her father and her bodyguard.
What happens if everyone finds out?