The word Tier is used in several different ways in ToME4, and on this wiki.
All in-game items are made of a material. There are 5 material choices for each type of item -- 5 types of metal used for swords, 5 types of wood/bone used for staves, 5 types of cloth used for robes, and so on. The tier indicates which of the 5 materials was used for this particular item. Tiers range from one to five, and can be found under the item's property screen. The tier number provides a general indicator of the relative power and value of the item.
In general, items of higher tier are more effective or more powerful, but egos on an item can quickly eliminate this advantage. A tier 1 item with two major egos may be significantly more useful than a tier 3 item with no ego. In addition, items of higher tiers will have higher requirements to use the item -- usually the primary stat for the item.
Tier of item is reflected in the name of the item, by the material it is made from. For example, "steel" items are always of tier 2. See material for a table of base item types or Item list for a table of all these for each item tier.
Your character's main stats (Strength, Dexterity and so on) only tell part of the story. You also have rescaled combat stats (Accuracy, Defense, Spellpower, etc.) which determine the effectiveness of many of your talents, or the strength of your defenses against enemy talents.
These combat stats are organized into a tier system (completely independent of the tiers used for item materials). The combat stat tiers serve two purposes:
- Points invested in a combat stat give diminishing returns when the stat is already beyond tier 1. It takes 2 raw points to boost a combat stat by 1 effective point when you're in tier 2, for example.
- The combat stats behind an attacker's offensive talent is matched against one of the defender's combat stats. If the attacker's tier is higher than the defender's tier, the defender will receive a cross-tier effect.
You can tell what tier your combat stats are in by the color of the number which appears in your popup box. (Hover the mouse pointer over your character's icon to make it appear.) The colors are encoded as follows:
Some of the zones you can explore in ToME4 are divided into tiers indicating similar overall difficulty, or similar availability. This is a rough guideline, as the true difficulty of a zone also depends on your character build, and on whether you receive an alternate layout in place of a standard layout (new in 1.0.3).