The Trident of Titans is an artifact from Heroes V. It goes in the slot and it enhances the hero's lightning-based spells by 50%. The Trident can be purchased for 6,000 gold. Lightning spells are weak in Heroes V; especially the early Lightning Bolt where the spellpower is low and there is hardly Destructive magic expertise, so starting with the Trident does not seem optimal. Even throughout the game it is not so useful, but if you play Svea or a Warlock hero it could be another thing entirely. One the plus side, the Trident sells for a better price than other minor artifacts.