From page to king Arthur

"Arthur, a page serving in the armory of Albion's royal palace, is secretly a prince. Twenty years ago, his father, King Uther—the ruler of Albion and humanity's greatest dragon slayer—was betrayed by his minister Mordred and met a brutal death on the battlefield.
Concealing his true identity, Arthur studied magic under Merlin. Merlin told him that to defeat Mordred once and for all and avenge his father, he must travel to the Isle of Avalon, compete in a tournament of mages, and draw the sacred sword of kings!
To gain passage to Avalon, Arthur chose to accompany Mordred's son, Agravain. Along the way, he endured humiliation and hardship, defeated a fearsome dragon, and rescued Guinevere—all to earn the right to draw the sacred sword, claim his vengeance, and lead humanity to victory over the dragons!"