[Bonus chapter] Just Like A Mafia Boss!
That made him quite envious of the Long clan. They got their hands over tons of dark gold cores. If he was just stronger, he'd have gathered lots of these cores from that time.
So instead of regretting the past or praying for fate and heavens to do the impossible for him, he saw in his training techniques a way out. Even if it was much slower than his current rising speed using the Devour ability, it was better than nothing.
Starting out from the high stage of gold grade, he'd depend entirely on his training technique, not Devour ability.
His luck wasn't that good actually. He didn't succeed in his first attempts, in his first one hundredth attempts. With every fail, he learnt something, modified and edited his new training manual, before trying it out again.
At many times, his failure didn't come with any price at all, but at most times, he suffered different degrees of backlashes.