First of all, let's get it out there that it's only a tool. Yes, it'll help Jay for his rise to the top, but it'll never be to the point where it becomes the most important part of the novel.
How does Jay gain EXP? What does it do?
- Through missions. It levels him up, which in turn gives him 1 AP and 5 SP.
How does he unlock missions?
- They're completely random.
Are there bottlenecks?
- Now then, there are two major bottlenecks for both Attributes and Skills.
• Attributes have 15 as the first, but that was easy to surpass for Jay, thanks to the system's healing rate which allowed him to surpass his body's limits. This is a bottleneck that even normal human can pass through hard work (strength, agility...) or genes (charm, appearance...).
Then there's the 20 cap. Basically impossible to pass without the system's extra AP points.
• Skills have a minor watershed every 10 points. The major bottleneck is at 40 points, and each point after that works exponentially.
Doesn't that mean that as long as he levels up, he'll become a god?
- Technically, yeah. But the EXP he requires to level up increases each time, so that's not gonna happen.
Isn't he immortal because of the healing rate?
- Nope. He will age and die like anyone else. The healing rate only helps him heal, nothing else. Think that's impossible? I decided it wasn't. Sue me.
But he can't die of anything besides old age then?
- He can die if his body gets blown up to pieces. Also if his heart gets pierced, but good luck doing that faster than the system can heal him.
Doesn't it mean he's untouchable?
- Is he? Think about it, his family and friends are all normal humans. Even Superman has his Achilles' heel.
Additional information: AP and SP attributed will be reduced to 1 every two levels 2 per level respectively once he reaches level 5.
Still skeptical? Keep in mind it's a fiction, then maybe if it pulls at your suspension of disbelief a little, it won't matter as much.
I'll make modifications as the story goes, but for now that's it!