Tide Lord: System Mage

A hundred years ago, meteorites fell from the sky, demonic tides arose, and monster lairs were everywhere. The human race was retreating steadily, and finally retreated to major islands to survive. Relying on the periodic fluctuations in the intensity of the demonic tide, you can land on the mainland when the demonic tide is at its weakest, collect resources, establish a territory, and charge magic stones. When you are unable to resist more and more monster attacks, you can retreat back to the island with full resources, and you become a demonic tide lord. "Wait, why did I travel to the game?" "Fortunately, it comes with its own game system. In that case, Deep Blue will add some points! Sound the horn of counterattack and make the world tremble!" "So what are you going to eat tonight? Fortunately, I learned the bread art and water making art in my memory... Why can I only rely on the system to cast spells?"