I Used the System to Become Invincible in the World

New writer, bear with me What? Do I have a system? What functions does the system have? Exchange, explosive cultivation, shopping mall, apprenticeship, harem... All these functions are available to you. So good! "Please also ask the host to complete the task quickly. If the task fails, the host will be directly obliterated." "Damn it, what mission do I have?" "Kill the devil!" This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.