To efficiently farm Stygian Stones as a Tier 4 player in Diablo IV, adopting targeted routes and strategies is essential for maximizing drop rates and minimizing time spent. At this stage, players have access to more challenging content and higher-tier dungeons, making it possible to gather stones more rapidly if the most effective methods are employed.

One of the most consistent sources of Stygian Stones is the high-level dungeon called The Pit. For Tier 4 players, running The Pit repeatedly is highly recommended because the boss fights inside have a higher chance of yielding stones, especially on higher difficulty settings like Torment or Nightmare tiers. To optimize your runs, focus on preparing builds that excel in fast boss kills classes or setups that can clear efficiently will help ensure you complete multiple runs in a shorter time frame. Additionally, coordinating with other players in groups can significantly increase drop rates due to shared kill speed and additional loot chests.

Another crucial route involves engaging with high-tier Nightmare Dungeons and Infernal Hordes. These events occur in specific locations and become more lucrative on Tier 4 due to their increased difficulty and loot quality. Prioritize maps and regions where these events spawn frequently, such as the Scosglen or Kehjistan zones. Completing these activities on Tier 4 provides rare chests and boss encounters that have improved odds of dropping Stygian Stones.

For more consistent farming, players should leverage the World Bosses and Tormented Bosses available at Tier 4. These bosses are scattered across Sanctuary and, when defeated, have the potential to drop multiple Stones. Targeting the ones with the highest spawn rates and focusing on areas where multiple bosses are close together can reduce travel time and increase farming efficiency.

Routine farming of the "Mother’s Gift" caches can also supplement Stygian Stone acquisition. These caches are often found in high-level zones or as rewards for completing specific quests or bounties. They sometimes contain Stones directly or items that can be traded for Stones, providing an alternate source outside dungeon runs and boss fights.

Utilizing fast travel points and pre-planning your routes through regions known for frequent boss spawns is crucial. High-value zones like the Dry Steppes or the Ashwold Cemetery often have multiple active events, making them ideal for a quick run that maximizes loot per minute.

The most efficient farming routes for Stygian Stones at Tier 4 involve repeatedly running The Pit with optimized, swift-clear setups, engaging in high-tier Nightmare Dungeons and Infernal Hordes, targeting World and Tormented Bosses, and utilizing caches and high-frequency spawn zones. Combining these strategies ensures steady progress toward collecting enough Stones to summon and defeat the endgame bosses that core players seek.