Otherworldly Mayhem monarch

Lin Feng, 18, reincarnated in a cultivation world; initially, he became a bandit, but after being kicked out of the bandit guild, the seal of the demon's gate was undone, and the cultivation world became apocalyptic; shortly after, he unlocked a system called «Otherworldly Mayhem system» which grants him three useful abilities: Undead Transformation/ Doppelganger/ Energy Devourer
What will he achieve with this System? Wealth, dominance, babes, or the throne as the mayhem monarch?