The Trident is the supreme divine artifact of the Sea Demons and is more powerful than Immortal Emperor True Treasures. Only those accepted by the Trident could become a Sea God.
After the death of a Sea God, the Trident returns to the Bonesea's forbidden zone. Every new Sea God visited the forbidden zone in order to discover its origin.
When Li Qiye entered the Bonesea's forbidden zone he used the Death Scripture's Death Record to forcefully seize the Trident. He, however, wasn't very interested in it and exchanged it for the Iron Maelstrom.
It is ancient and unadorned with many runes floating around it.