I'm Only Three Years Old, What the Hell Is the Old Man's Counterattack System?

[It has been detected that the host has reached seventy years old, which is a good age for struggle. The old man's counterattack system has been activated] [Ask the host to kill any creature in the Qi training stage to show determination] [The creature in the Qi training period closest to the host, the ninth level of Qi training, a monster, and a powerful ant were detected] [Reward: Cleanse the tendons and cut the marrow] Cai Xu looked in the mirror, looking at his short limbs, his pink face lost in thought. Me, seventy, old man? Cai Xu saw ants on the ground again. Is this the legendary monster at the ninth level of Qi training? ..................... Many years later, Cai Xu stood in space, looked down at all living beings, and couldn't help but sigh, "Invincible is so lonely."