The Sword of Youth (至源の剣, shigen no tsurugi) is a magical blade that appears only in the Light Novel “My one and only Prince”.
This is one of the two legacies left by the original King of Elgo (The Fountain of Youth being the other one). Being the sword created and used by the original King of Elgo. It was passed down through every generation in the Affinity family, the royalty that rules the Saint Kingdom. It is said that only those that inherited the King of Elgo’s blood are able to use it, therefore, being able to use this sword has become the symbol o the true king.
It is said to be the strongest sword in the whole universe. When activated it releases many flashes of light made of pure Mana. This mana energy restore the user’s health and can make even a old man move like a teenager. It’s blade can release many magic projectiles in just one swing. Furthermore, it also has the power to create many different types of swords that attack at the same type, with strength needed from the user. The explanation to this is that this sword HAS to be the absolute blade, thus it has the ability to copy any other type of sword it comes to face. It is unclear if it also has the ability to copy special power from other magical blades such as the Magical Blades from Summon Night 3.