The Ruinous Oath is a Stage 10 fishing rod in Fisch, sold inside the Crimson Cavern for a flat cash price. It is built as a straight upgrade to the Luminescent Oath, pairing very high Luck with a passive set that can guarantee the Mastered mutation during a perfect catch. Getting it is less about luck and more about clearing two hard gates first.
Quick answer: Reach Level 750, fill the full Shiny and Sparkling bestiary for the Crimson Cavern, then buy the Ruinous Oath for 5,000,000 C$ from the pedestal next to the Crimson King.
Ruinous Oath requirements in Fisch
You cannot buy the rod the moment you walk into the Crimson Cavern. The purchase only unlocks once you meet all three conditions below at the same time.
| Requirement | Value |
|---|---|
| Level | 750 |
| Bestiary | 100% Shiny and Sparkling bestiary for the Crimson Cavern |
| Cost | 5,000,000 C$ |
| Location | Pedestal next to the Crimson King, Crimson Cavern |
The bestiary requirement is the slow part. You need every Crimson Cavern fish recorded in both the Shiny and Sparkling states, not just the standard catches. Until that bestiary is complete, the rod stays locked even if you have the cash and the level.
How to buy the Ruinous Oath
You will know the purchase worked when the rod is added to your inventory and the Rod Journal grants 2,000 XP for obtaining it.
Ruinous Oath stats
| Stat | Value |
|---|---|
| Lure Speed | 95% |
| Luck | 300% |
| Control | 0.08 |
| Resilience | 25% |
| Max Kg | infkg |
| Disturbance | +4 |
| Hunt Focus | Colossal Ancient Dragon +3 |
| Line Distance | 150m |
The rod leans on high Luck and unlimited weight capacity, with moderate Lure Speed and low Control. That low Control makes the reeling bar narrow, so handling takes precision until the perfect catch passive kicks in.
Passive abilities
The Ruinous Oath’s value comes from its passives, which reward clean perfect catches with a guaranteed top-tier mutation.
- A 5% chance for slashes that add 2% progress with no stun every 0.25 seconds, and that slash chance climbs by 8% each second up to 100%.
- A 25% chance to apply the Mastered (8×) mutation on a normal catch.
- A 15% chance to instantly grant a large chunk of progress at the start of the minigame.
- During a perfect catch, the control bar shrinks while progress speed rises by 5% per second and resilience scales up to 1.5×, with a 100% chance for the Mastered (8×) mutation.
Note: The Mastered mutation overrides other mutations on the fish, with the exception of Shiny and Sparkling. The gradually increasing progress speed can also bypass Progress Locked fish.
Recommended enchantments
Different enchantment pairs suit different goals. Pick based on whether you are grinding cash, chasing weight, or aiming for Keeperbound results.
| Goal | Enchantments |
|---|---|
| Keeperbound | Starforged Spirit + Sanctified |
| Optimal grinding | Mystical + Sea Prince (Resilient if no Exalted Relic) |
| Control and stop chance | Herculean + Cryogenic (Controlled if no Exalted Relic) |
| Maximum weight | Sea Overlord + Sea Prince (Sea King if no Exalted Relic) |
Rod Mastery rewards
Once you own the rod, its Mastery quests start at Level 1000 and unlock cosmetic and stat rewards as you complete them.
| Quest | Requirement | Reward |
|---|---|---|
| True Mastery | Catch 1,000 Mastered fish | +15% Fish Size for the Ruinous Oath |
| Ruinous Cataclysm | Catch 5 Apex fish | Ruined Title |
| Ethereal King | Perfect Catch 2 Colossal Ethereal Dragons | Ethereal Bobber |
| Grand Reward | Complete all quests above | Golden Ruinous Oath skin |
If the purchase prompt does not appear at the pedestal, the usual cause is an incomplete bestiary or being short of Level 750. Confirm both gates and the 5,000,000 C$ balance, then return to the Crimson King to finish the buy and start working through Mastery.
