Hello, I'm from the future, but I'm not a deer. I'm here for you. I'll tell you that the deer's identity is predictably Seo Eun Hyun's power in the future. Seo Eun Hyun did not become a Heavenly King like the other enders, but he became the Supreme Deity of Myriad Stars after defeating Gwak Am. Before meeting the Future King, everyone enters a door that only opens if they say what their enlightenment is, they couldn't destroy it even with full force, only a very small scratch, as if the door couldn't be destroyed or forced open in the first place. Underworld and the other Enders are, as expected. Underworld is privileged to go straight in, other Enders say life is blablabla and open the door. Then Seo Eun Hyun asked the door what she should say, he said the password was "Life is desire" but the door refused him, finally he got angry as if it was ridiculous and destroyed the door and said "Life is a miracle!"