Invincible Leveling

Qin Tian transmigrates by accident. His body is frail and sickly, and his dantian is damaged, leaving him unable to cultivate qi. But Heaven takes pity on him and grants him an upgrade System. A good-for-nothing? That's all in the past... He can level up by killing monsters, with ease, and never has to worry about cultivation again. Killing monsters lets him level up, and so does killing people. The sect masters who seem untouchable and awe-inspiring to everyone else are glittering BOSSes in his eyes... I can level up, so what have I got to fear? When so-called geniuses hit a bottleneck they can't break through, all I need to do is kill a few more demon beasts. Though sect leaders, clan leaders, and world rulers would be even better. For the sake of my path to godhood, offer up your lives!