Drops in UNDERDEEP depend on the tile you are standing on and on the kind of fight, not on your character: every stat, every piece of gear and every job level is irrelevant to drop chance. The Underdeep drop rates are pure RNG on top of a counter, which means the only thing you control is where you fight.
Underdeep drop rates: the two loot tables
Corridor fights are the random encounters you pick up while travelling, and they use one loot table. Static fights are the ones that sit at dead ends, and they use a second and much better table - but only the first time you clear that tile on any given exploration.
Tile bands decide the row
Every tile is assigned a band from 0 to 9 (the first dungeon has no band-9 tiles), and the band picks the row of the table.
Corridor fight table:
| Band | Normal | Rare |
|---|---|---|
| 0 | 99.9% | 0.1% |
| 1 | 99.8% | 0.2% |
| 2 | 99.7% | 0.3% |
| 3 | 99.6% | 0.4% |
| 4 | 99.5% | 0.5% |
| 5 | 99.4% | 0.6% |
| 6 | 99.3% | 0.7% |
| 7 | 99.2% | 0.8% |
| 8 | 99.1% | 0.9% |
| 9 | 99.0% | 1.0% |
No Super Rare or SSR ever drops from a corridor fight.
Static fight table:
| Band | Normal | Rare | Super Rare | SSR |
|---|---|---|---|---|
| 0 | 98% | 2% | - | - |
| 1 | 97% | 2.99% | 0.01% | - |
| 2 | 96% | 3.98% | 0.02% | - |
| 3 | 95% | 4.97% | 0.03% | - |
| 4 | 94% | 5.96% | 0.04% | - |
| 5 | 93% | 6.95% | 0.05% | - |
| 6 | 92% | 7.94% | 0.06% | - |
| 7 | 91% | 8.93% | 0.07% | - |
| 8 | 90% | 9.85% | 0.15% | - |
| 9 | 89% | 10.8% | 0.19% | 0.01% |
The Luck Counter guarantees a floor
The Luck Counter is the in-game Manual's name for the pity timer, and it guarantees a floor on your luck. Every kill raises the Rare counter; kills on bands 1 to 9 also raise the Super Rare counter on static fights, and band-9 static kills raise the SSR counter too.
| Counter | Threshold |
|---|---|
| Rare | 9 |
| Super Rare | 864 |
| SSR | 9900 |
When a counter reaches its threshold and the roll comes in below that rarity, the item is upgraded to the pity rarity and that counter resets. The SSR counter is effectively unreachable: the largest number of band-9 tiles in any dungeon is 17, in dungeon 5, so you are unlikely to ever accumulate 9900 of them.
Upgrade suffixes
A drop can also carry an upgrade suffix, which comes from a second roll:
| Suffix | Chance |
|---|---|
| Regular item | 98.1% |
| +1 | 1.9% |
| +2 | 0.09% |
| +3 | 0.01% |
Where the best drops live
The practical rule is to fight the bosses and the static encounters and ignore the corridor fights, then head for the highest-band tiles you can reliably one-shot. The band-9 tiles are known and fixed, with X and Y coordinates starting at 0,0:
- Dungeon 4 (11 tiles): 11,0 16,2 2,4 7,5 8,6 4,8 6,8 9,8 16,11 15,14 16,14
- Dungeon 5 (17 tiles): 3,3 4,3 5,3 8,3 9,3 5,5 2,8 3,9 9,9 4,11 7,11 13,12 14,14 5,15 8,15 15,15 7,16
- Dungeon 6 (13 tiles): 0,4 8,4 3,5 8,6 10,6 4,7 11,9 2,10 7,10 5,11 7,11 0,12 8,12
What those drops unlock is a different question, and it is covered in the item rarity guide.
What happens to duplicate drops
Your eight Loot slots fill up fast, and the copies are not wasted - duplicates are converted into Coin when you return from the run. The selling items guide explains how that works and what Coin buys.