Mark of Mastery exam
The Mark of Mastery exam (マスター承認試験, Masutā Shōnin Shiken?, lit. "Master Qualification Exam") is an event which serves as a test for those strong of heart that have been chosen by the Keyblade to become Keyblade Masters.
The criteria for passing is up to the Keyblade Master serving as the examiner. Apprentices of Keyblade Masters who pass the test have two choices:
The exam itself varies in its process, with some being simple duels, as seen with Terra and Aqua's exam, and others being entire journeys to resolve pressing issues, such as Sora and Riku's quest to awaken the Sleeping Worlds. If outside forces interfere with the exam, the examiner will determine if the applicant still meets the criteria for passing. Eraqus failed Terra for using darkness, due to his own aversion to it. Despite Sora also gaining the power of waking in the exam, Yen Sid did not pass him due to Xehanort making him lose most of his powers.
Kingdom Hearts Dark Road
As part of their Mark of Mastery exam, Hoder, Helgi, Heimdall, Vala, Vali, Vidar and Sigrun travel to other worlds, but due to conflicting beliefs among them and the loss of Hoder, the remaining students were struck down by Baldr, who was possessed by Darkness. Years later, Eraqus and Xehanort took the exam themselves passing and earned the title of Keyblade Masters themselves.
Kingdom Hearts Birth by Sleep
After an intense evening of training, Terra and Aqua arrive before Master Eraqus, with their friend Ventus eagerly watching. Master Eraqus announces that his old colleague Master Xehanort has come to help judge their skills, then warns Terra and Aqua of the strong heart and will required to pass the test, and that their fate will be decided through the exam. As soon as his apprentices are ready, Master Eraqus proceeds to summon several Orbs of Light for them to battle, but Master Xehanort covertly infuses the orbs with darkness, forcing Ventus to help defeat them as well. However, Eraqus allows the test to proceed.
Once the orbs have been destroyed, the second stage of the Mark of Mastery exam begins. Terra and Aqua engage in a fierce battle, and as Terra begins to lose the battle, his inner darkness begins to emerge, but he quickly dismisses it. When the battle has ended, Master Eraqus acknowledges Terra's great strength, but chooses only Aqua to become a Keyblade Master due to Terra's reliance on his darkness. Master Eraqus states that he expects Terra to try harder the next time; he then tells Aqua he will later inform her of her new duties as a Keyblade Master, leaving behind a confused Terra, who soon leaves to get his head together.
In the meantime, Mickey Mouse takes his own Mark of Mastery exam under his master Yen Sid by journeying through different worlds via his Star Shard and aiding Ventus and Aqua in their battles against Master Xehanort, Vanitas and the Unversed. Not long after the disappearance of Terra, Ven, and Aqua and the appearance of Terra-Xehanort, he returns his Keyblade and Star Shard to Yen Sid, believing he has failed; however, Yen Sid hands the Keyblade back to Mickey to show that he has, in fact, passed.
Kingdom Hearts Re:coded
Kingdom Hearts 3D: Dream Drop Distance
As their Mark of Mastery exam, Yen Sid assigns Sora and Riku to travel the World of Sleep and awaken seven worlds which remained submerged in sleep following Ansem's defeat, but a young Xehanort appears to hinder their progress. Initially, Sora and Riku hesitate to take the exam, Sora believing that he is unbeatable as he is, and Riku concerned about his past experiences with the darkness.
Despite the interference of Xehanort and his new Organization XIII, Yen Sid states that both Sora and Riku deserve to become Keyblade Masters, but since Riku went to the Realm of Sleep again to save Sora, who has lost most of his power because of his near possession, Yen Sid names only Riku as a Keyblade Master.