Prerequisites and Quest Start
Before you can accept the rematch wish, I recommend confirming three things:
You have defeated the Savage Beastfly inside the Chapel of the Beast.
You have progressed through the second Act.
You have defeated the Cogwork Dancers.
Once those requirements are met, head to Bellhart and check the board for the Wish. Accept it. Then travel to the Far Fields Bellway Station. Tracking the beast from here is possible, but it takes time and offers no extra rewards, so I always skip the tracking step.
Reaching the Rematch Arena
From Far Fields Bellway Station, take the left passage. Then head down, and after that move right. You will eventually enter the same section as the Four Chorus. That is where the Savage Beastfly rematch takes place.
The arena here is more dangerous than the Chapel because lava surrounds the sides, and the boss can destroy platforms when it performs its slam-down attack. Keep this in mind before you trigger the fight, because losing a platform at the wrong moment can push you into a very bad position.
Recommended Loadout
This is the setup I use after many failed attempts with other tools. Bring the following:
Tool
Why It Works
You can lay these out before the fight begins. If the boss touches them, the burst damage is huge.
This gives you a safe long-range option while the Beastfly is flying around.
It adds Venom to your tools, so every Sting Shard and Curveclaw hit becomes much more effective.
The key is preparation before the fight starts. With the Pollip Pouch adding Venom, your placed Sting Shards can deal so much damage that the encounter ends in less than a minute. I usually place several Sting Shards near the centre before triggering the boss, then immediately switch to Curveclaw for follow-up hits.
Fight Strategy
After the Beastfly dies, pick up the Horn Fragment. Then return to the Bellhart quest board. Completing the Wish will reward you with a Mask Shard, which is required to increase your maximum health.
This is one of those Silksong quests that feels unfair at first, but the right tools completely change the fight. I have not found a faster or safer method than the venom-backed Sting Shard opening. Even if you miss a trap or two, the Curveclaw gives you enough range to finish the job without standing in the lava. Good luck with the rematch, and keep moving.
That same preparation mindset carries over beyond the game itself. Just as you scout the arena and place your tools before the Beastfly fight begins, it pays to plan your purchases before you commit. Silksong's DLC, a better controller, or even a Steam gift card can show up at a much lower price if you are willing to wait for the right moment.
Instead of refreshing store pages every day, you can let this price tracking tool watch the price for you. Set an alert, keep playing, and you will get notified when the price drops—so your wallet lasts as long as your determination.