As part of Genshin Impact's newest event, The Chalk Prince and the Dragon, players are tasked with powering up an ancient, magical sword called the Festering Desire. During the second Act of this event, one of the objectives is to get the unique weapon to refinement rank 2, something that under normal circumstances would be impossible without getting a second copy of the weapon.
Though 4 and 5-star weapons in Genshin Impact are by default more powerful than 3-star weapons, they are also more difficult to refine. Since refinement is such an important part of getting a weapon to its maximum potential, there are some rare cases where a fully refined 3-star weapon is better than a base 4-star weapon. The Festering Desire is unique in that it has two ways it can be refined, however.
As an event weapon, it's impossible to get another copy of Festering Desire. Players can't get it from wishes like they would any other 4-star weapon, and there's no way to forge or duplicate it at the moment either. Instead, The Festering Desire can be refined by using Festering Dragon Marrow, a unique event item.
In order to get Festering Dragon Marrow, players need to enter the event shop. Within the shop there are three different categories: Glimmering Essence, Warm Essence, and Miraculous Essence. Glimmering Essence is the first event currency that players will gain access to and becomes available during Act 2 of the event, and can be used to purchase one Festering Dragon Marrow. After buying it, players can refine the sword to rank 2 as normal, selecting the Festering Dragon Marrow as the material instead of a copy of the weapon.
Naturally, players will need to stock up on Glimmering Essence if they are to be able to afford the marrow item. It's the most expensive thing in the shop, running for 600 Glimmering Essence, so it will take a little bit of grinding to save up for. Act 1 requires players to collect Rime-Worn Crystals and Fragments, but Act 2 sees players battling at testing grounds events. Every time players complete a testing grounds event (marked as a red circle on the map), they are awarded with 120 Glimmering Essence, so it will take six completions of these trials to buy the Festering Dragon Marrow.
In order to refine the sword further, players will need to wait for the event to open up more. At the time of writing, only the first two acts are available, but in the coming days more acts will open up. Act 3 of The Chalk Prince and the Dragon should introduce Warm Essence, which players can spend 600 of to buy another Festering Dragon Marrow, and the fourth and final act will add Miraculous Essence. The final Festering Dragon Marrow costs 400 of this new currency.
Genshin Impact is available now on Mobile, PC, and PS4, and later on Switch.