Adding Item Drops and Loot in Elden Ring (DSMapStudio Guide)

Making an enemy drop a custom item in Elden Ring trips people up for one reason: drop chance isn't a percentage you type — it's a weight relative to the other outcomes, including the chance of dropping nothing. Set an item's weight to 100 next to a "nothing" weight of 900 and you've made a 10% drop. Miss that and your "10% drop" is either guaranteed or never appears. Second thing: Elden Ring splits loot into two tables — ItemLotParam_enemy for enemy drops, ItemLotParam_map for world treasure — so which param you edit depends on where the loot comes from. You'll need an Elden Ring project open (Elden Ring setup); general workflow in the Param Editor hub.

How drops are wired

Three pieces connect:

• NpcParam — each enemy's definition references an enemy drop table (an ItemLotParam_enemy row ID). On death, the game rolls that table.
• ItemLotParam_enemy — the drop tables. Each row is one table of several slots.
• Slots — each row has numbered slots (01–08); a slot specifies an item by ID + category, a weight, and a quantity. One slot is usually left empty to represent "drop nothing."

World pickups and chests use the parallel ItemLotParam_map instead, referenced by the map's item placements. The slot mechanics are identical.

Drop chance is weighted, not percent

Each slot has a base point value — its weight. A slot's chance is its points ÷ the total points of all slots in the row. There's no percentage field; you build percentages by balancing weights against an empty slot.

Worked example — a 10% chance to drop a sword:

• Slot 1: the sword, weight 100.
• Slot 2: empty ("nothing"), weight 900.
• Total = 1000, so the sword drops 100 ÷ 1000 = 10%.

Guaranteed drop? One slot, no competing weight. 1%? Item weight 10 against a nothing-weight of 990. Think in weights, not percentages, and every drop rate is arithmetic.

Adding a drop to an enemy

1. Find the enemy's drop table. In NpcParam, locate the enemy and note its enemy ItemLotParam reference (the drop-table row ID).
2. Open ItemLotParam_enemy and find that row. If several enemies share it and you only want this enemy to drop your item, duplicate the row to a new ID (Ctrl+D, re-ID) and point this enemy's NpcParam reference at the new row.
3. Fill a slot. In an empty slot, set the category (weapon, protector, accessory, goods), the item ID (the actual item's row ID — e.g. an EquipParamWeapon ID for a weapon), the quantity, and the base point weight.
4. Balance the chance. Set or add an empty slot's weight so the total produces the percentage you want.
5. Save (Ctrl + S).

If you duplicated the table in step 2, double-check the enemy's NpcParam now references your new row, or the change won't apply.

World / treasure loot

For an item found in the world rather than dropped, the same slot-and-weight system applies in ItemLotParam_map. The difference is what points at the table: map item placements reference ItemLotParam_map rows, so to change a specific chest or corpse pickup you edit the ItemLotParam_map row tied to that placement. Category/item-ID/weight fields work exactly as for enemy drops — do one, you've done both.

Save and test

Ctrl + S, point ModEngine2 at the project's mod folder, launch. Kill the enemy (or open the treasure) and confirm. Because the roll is random, test a guaranteed version first — temporarily make your item slot the only weighted slot — to confirm the wiring, then dial in the real rate. Reopen and run modified on ItemLotParam_enemy to verify the row saved.

Common loot mistakes

The item IDs you reference come from params like EquipParamWeapon — dropping a custom weapon? Make it first with the add a weapon tutorial (same concept in Elden Ring), and use CSV export/import to edit many drop tables at once.