Lock and Key and Girl's Heart

(The author is very busy every day, so sometimes he may stop updating for a while) The monster that brings destruction, the incarnation of despair, "Unlocked"——To deal with such a natural enemy, the sleeping girl wakes up. However, they do not take sides. Girls possess incomparable power, so to humans, they are also time bombs that will explode at some point—— So at this time, it's the savior's turn to take action! "Eh... You mean, me?" The young man pointed at himself blankly, obviously not understanding what he just said. This is a story that starts with you... The savior protects the world and meets the girls trapped in the cage. Isn't this the best youth boy meets girl! "What on earth were you talking about from just now... By the way, your description sounds so much like "The Battle of XX"——" Don't worry so much about the details! So, are you ready for that kind of realization—— Go and unlock the hearts of girls and fall in love with them! ?