Cast on a nearby surface, it explodes for <effect> when enemies come near.
Runes are useful offensive spells belonging to assorted schools that create symbols upon the ground where the player is pointing which enemies will trigger when they walk over them.
All runes have a casting circle that appears when you cast the spell, unique to the particular rune that is being cast. These circles can layer over objects in the terrain to some extent, but regardless, when an enemy comes within melee range of the casting circle the effect of the spell is triggered. Only one rune of any type can be active at a time. Casting another will negate the first.
You and your followers and summons will not set off your own runes, but there are some quest-specific followers who can set them off. You can usually tell whether a follower will trigger a rune if when sneaking in front of them, you get the open-eye symbol indicating that you're being watched. All followers regardless of what circumstances have them following you will be affected by runes if they are nearby when an enemy sets them off.
While the spell is intended to be used as a delayed-reaction trap, you don't necessarily have to use it that way. You can cast it directly under an enemy's feet and it will go off right away, essentially acting as a ranged, instant-cast spell which cannot miss. Furthermore, you can set off runes (your own or others) using any projectile spell.
The following spells use the Rune effect. Following each spell is the school it is contained within and the specific variant of the effect that it uses:
- Killing or harming an NPC with a rune spell is not considered a crime provided that you are hidden at the moment the rune is set off. Provided the NPC survives the blast, it will still become aggressive towards you.
- Many shouts will detonate any rune trap they hit.
- You can avoid setting off enemy runes with the Light Foot perk in the Sneak skill tree.
- If the decal quantity setting is set to "None", runes will appear invisible except for their particle effect, though it is difficult to notice. However, the runes can still be set off.
- To fix this, go to advanced options and set the decal quantity to "Medium" or higher.