Alone: Tale of a monster hunter

It was a normal world. Everyone lived a normal life until one day, people started disappearing one after another. That was a year ago. At first, people thought it was a usual case of kidnapping. But as time passed, the disappearances further escalated. Numerous operations were launched to discover the whereabouts of the missing people. However, these attempts were futile. No one who went missing was ever seen again. It was a matter which didn't concern Zaen. An 19-year-old dropout whose life wasn't as messed up as the others. His parents had abandoned him and his little brother. But as long as he had his little brother with him, the world could go to hell for all he cared. Until one day his brother, Aeron didn't come home after his school. He looked for him everywhere... but it was the same. He too had vanished like he never existed. The police were no help either. They simply declared him 'missing'. And just like that Zaen lost the only person he had in his life. It had been a week since Aeron's disappearance. Zaen had lost all hope. Until... he received a text on his phone. It was in a language he had never seen before but somehow he knew what it said. [Congratulations mortal! You have been selected to be humanity's champion!] [There are unclaimed items in your inventory. Claim them to get briefed on your first task. You can access the inventory just by thinking about it.] What is going on here? Humanity's champion? Inventory? As soon as he thought about inventory, a bright screen appeared in front of him. The next moment his attire was completely changed and he had a knife in his hands. [MIssion 1: RECLAIMER.] [Introduction: There have been mysterious disappearances in your area. Find and eliminate the cause of the disappearances.] [Task: Kill the Charred Ghoul hiding in the local park.] [Rewards: ???] [Failure to complete the task would result in the death of all the disappeared humans.] [Time Limit: 2 days.] Zaen didn't know what was happening. But all he cared about the chance he had been given to save Aeron and he wasn't going to waste it. Even if he had to die. **** Cover art link: https://weheartit.com/entry/311465796 (if anyone has any problems with it, then please leave a review to let me know. All rights belong to the artist)