The Reincarnated Mercenary's Only Skill is Item Box

"No one ever helped me no matter how much I suffered. So, tell me...why would I help others if there's no benefit to it for me?" After being sold off by his parents to human traffickers due to a physical deformity and ending up as a resident of the underworld, a jaded mercenary is killed during a mission gone wrong. "If only there was a way to carry my entire arsenal of weapons without weighing myself down..." As he dies, he suddenly finds himself waking up in a younger, unfamiliar body, in an unfamiliar world. He discovers he is now in a rundown orphanage located in a medieval world full of Magic and Monsters, his new body weak and frail. His new name is Jaedfern Meraled, or Jade for short. But he's not alone in being sent to this world...along with him is the Angel Arkiela, who was banished to this world for interfering with the human world out of boredom. Specifically, she used her powers to feed and amplify people's impulses and intrusive thoughts, including those around Jade, whom she targeted to "mess with," subsequently ruining his life. She then claims that their lives are now intertwined...if one of them dies, so will the other. While uncertain whether she's being honest or lying to ensure he can't kill her, Jade can't risk putting it to the test, so he errs on the side of caution. Grudgingly, he decides to accept her presence, having no other choice. With that settled, she reveals that when people are reincarnated with their memories intact, they're given OP powers, usually as a reward or consolation for their circumstances in their previous life. She then checks what abilities he's been bestowed with. In this world, there are three main elements to a person's Magic: their Magic Class, which is the core of their abilities; their Mana Pool, the quantity of Magical energy they possess; and their Skills, special abilities that include active powers like Appraisal and passive powers like Heat Resistance. Each person possesses three Skills, without exception. As for Jade, his Magic Class is...well, he doesn't have one. And his Mana Pool...is nonexistent; he possesses no Magical energy whatsoever. Finally, his Skills...he only has one, titled "Mercenary's Item Box," a dimensional storage power with a number of abilities that can be unlocked by Leveling Up the Skill. Most people who are reincarnated are given OP powers, rewarded for either living a virtuous life or as consolation for living a tortured life. But sometimes, people who've lived sinful lives can be punished instead, bestowed with the bare minimum of abilities in worlds where such abilities are everything. And Jade is the latter. However, Jade may not necessarily be as bad off as it initially seems...because within his Item Box is every weapon he owned during his previous life, weapons that don't exist in this world. Will it give him enough of an advantage to survive, and ideally thrive, in this medieval world rampant with violent crime and dangerous Monsters? One thing's for sure, it certainly won't be easy.