I Got the Rumble-Rumble Fruit from the Start, and You Call This Weak Lightning?

A Dayun truck sent Siyuan, who was on his way to buy a watermelon, to another world, where he changed classes into a subpar-level lightning wielder. A laughable current, a painfully weak power level, a bleak future... Just as his prospects looked completely hopeless, a Devil Fruit appeared before him! The watermelon he'd bought had transmigrated too, and had even become the Rumble-Rumble Fruit! From then on, a true god descended. “Beneath the heavens, only thunder is eternal. When lightning strikes, the end begins.” “My breath stirs the clouds. My gaze is the fuse.” “You mere mortals think yourselves worthy to face heaven's wrath?” “This strike is called Heaven's Retribution!” “I come bearing heavenly thunder!” “God says: Divine punishment!” The Behemoth Clan, the Insect Swarm Clan, the Ghost Domain Clan, the Demon Emperor Clan, and the Human Clan... The five great races of the world had kept one another in check, with none able to overpower the others. Siyuan's arrival shattered the balance completely. The other four races all lost it and started cursing! “You call this subpar-level lightning!?”