Runes
There are 18 runes, in this fixed order: El, Eld, Tir, Nef, Eth, Ith, Tal, Ral, Ort, Thul, Amn, Sol, Shael, Dol, Hel, Io, Lum, Ko.
Using. Use a rune on an item you carry that has a free socket. Runes fill the sockets in order, so think about the order before you socket.
Each rune has a small bonus on its own, different for weapons and for armour:
- El adds attack speed to a weapon and armour to armour.
- Tir gives life on hit or life regeneration.
- Ral gives fire damage or fire resistance, Ort lightning, Thul cold.
- Tal and Amn give life leech.
- Sol adds critical damage or physical damage reduction.
- Dol adds spell damage or maximum mana.
- Io adds life, Lum adds mana, Ko adds elemental damage or all resistances.
Movement speed from the runes Ith, Shael and Hel together counts only up to a total of about 9% across all your gear.
Where runes drop. From monsters of at least the rune's level, with the lower runes far more common than the high ones. Bosses drop two or three. El is common, Ko is the rarest thing you will find. Lion caches and the runesmith provide more (Lion Caches (Drume)).
Upgrading. The runesmith NPC combines three runes of one kind into one of the next for the runes El to Ort, and two runes for the runes above that, for a fee in gold. Upgrading never beats farming, but it recycles small runes.
Runewords form automatically when the right runes sit in the right order in a Normal base with the right number of sockets (Runewords).
Corruption. If a Vaal Orb unravels a runeword, the runes stay in their sockets and give their own bonuses again (Corruption and the Vaal Orb).