The Nobody's Island Conquest

Protagonist crashes on a deserted island, activates 'Desert Island Beauties Registration System', becomes a leader. His former boss arrives; protagonist defeats them. He gathers four beauties. Drug dealer Álvaro takes the women hostage. Protagonist awakens hidden power, defeats Álvaro with a military doctor. Saved by the four women, he demands they kiss him to leave. He returns to the city with them, becoming the new king.