Item Rarity Calculation in Eternal Odyssey

Overview

In Eternal Odyssey, our rarity drop system balances fair item access across all monster types, while maintaining the distinct rarity and challenge of certain items.

For instance, it's much easier to find Leather Boots from Trolls than Boots of Haste from Necromancers. Instead of a fixed global rarity system, we use a Local Rarity system that calculates rarity dynamically based on each item's individual drop rate and the monster tier. To further balance the system, a maximum cap is set for rarity chances, ensuring players experience a balanced progression.

Global Rarity Chances

The base chances for item rarities are globally defined as follows:

Rarity	Chance (%)
Common	10
Uncommon	2
Rare	0.5
Epic	0.1
Legendary	0.02

These global chances serve as a baseline and are modified by specific item drop rates and Monster Tiers.

Local Rarity Chances

Local rarity chances adjust these global values by factoring in each item's base drop rate. Here’s the process:

1. Determine Drop Chance: Identify the base drop rate from the monster's loot table.

2. Scale Factor: Convert this drop chance into a scale factor; items with lower base drop rates are scaled higher, making them relatively rarer.

3. Adjust Rarity Chances: Multiply global rarity chances by this scale factor to calculate the local rarity chances.

4. Cap the Chances: Ensure the resulting local chances do not exceed predefined maximum values, maintaining game balance.

Maximum Chances

The following caps are set to maintain balance, representing the maximum allowed chances per rarity tier:

Rarity	Chance (%)
Common	45
Uncommon	21
Rare	8
Epic	3
Legendary	1

Monster Tiers and Rarity Scaling

The rarity chances are further modified based on monster tiers. Each tier has an associated scaling multiplier, increasing the rarity chance as tiers become more challenging. Here’s how monster tiers impact the rarity chances:

Monster Tier	Rarity Scaling Multiplier
Elite	1.025
Champion	1.05
Overlord	1.075
Insane I	1.1
Insane II	1.2
Insane III	1.3
Insane IV	1.4
Insane V	1.5
Insane VI	1.6
Insane VII	1.7
Insane VIII	1.8
Insane IX	1.9
Insane X	2

Strategy

Understanding these rarity mechanics allows players to plan their battles, maximizing their chances for rare and powerful items. Higher monster tiers provide better chances for high-rarity items, while item-specific drop rates ensure that legendary items retain their value across all encounters.

For more information on unique monster encounters and how rarity scales with these encounters, refer to the Unique Monsters Stats Table page.