Raid: The Blacksmith

"Okay, so first off, my Innate Mana is incredibly low. Way too low to even be classified as a bona fide Warrior. Haha, totally funny God!! If you're even there anyway! Second, I spent three years, three whole years! Training to increase my Overall Mana through Accumulated Mana, but guess what? All I get as a result is a measly tenth of the Mana of what an average Warrior would normally get, emphasis on the 'average'! Get me!? But that's cool, that's cool, no that's fine, that's perfect, real peachy, totally not bumbed out about it! What? I'm lying and it's not fine? And I'm actually bumbed out about it? Sh-Shut up, you don't know anything!
Anyway, what's third, you ask?
What? You didn't ask? Well I'll tell you anyway, I'm an F-Rank, that's right, an F-Rank. The only one in the world at that. So basically, I'm the weakest Warrior in existence. Ain't that something? But you know what? That's also fine, 'cause I don't care...
No really I don't. It's true, stop doubting me already, I can see your face through the fourth-wall! Yeah, that's right, better watch yourself. So what if I'm the weakest Warrior, huh? I'm still capable, I just have to do my best, push passed my limits! Yeah, 'make do with what you have' is what I always say. What? I'm lying again? When have I ever said that? Again, shut up, you don't know anything!"
***
In a world where monsters from many portals called Dungeon Gates threaten mankind as we know it and half of the world's population Awakens as superhumans with skills and the ability to manipulate Magic in order to pass through said Dungeon Gates to clear the Dungeons, Raid, a 19-year old orphan finds he has no choice but to pick a very weak Class after Awakening as a Warrior due to his low Mana Capacity, the only F-Rank Class in the entire world, Blacksmith. Faced with the cruelty of the possibility of being seen as the weakest Warrior of all time, he decides to not let it hold him back. Follow Raid on his journey to make the most of the cards he's been dealt, even if those cards are...urgh, do I really have to say it?
"Yes, yes, you do"
Fine. Even if those cards are...pretty shitty cards.
"Yeah, that's right, you heard the author. Even as the weakest Warrior, I'll show all those other High-Ranked Warriors what's what! Tag along for some fun if you're interested"