The Ring of the Midnight Sun is considered a Diablo IV gold world drop, which means it is not locked to a specific quest or single enemy. Instead, it can appear in loot tables across different forms of endgame content. The following methods are the best ways to hunt it down:

Nightmare Dungeons – These dungeons provide some of the richest loot opportunities in the game. Higher-tier Nightmare Dungeons increase your chances of unique drops, making them the most consistent option for farming.

World Bosses – Ashava, Avarice, and Duriel can all drop unique rings, including the Ring of the Midnight Sun. Since these bosses spawn on schedules, it pays to track timers and join large groups for efficient farming.

Helltide Events – The Chests of Mysteries within Helltide zones are excellent sources of jewelry. Spending Aberrant Cinders on ring-specific or general jewelry chests gives you a focused chance at finding the item.

Obol Gambling – The Purveyor of Diablo IV Items for sale Curiosities lets you spend Murmuring Obols on jewelry caches. This is luck-driven, but it's a good supplemental method when you have extra currency.