Overview
Hide Level is very important to thieves. A thief's Hide Level determines whether the thief will be seen by a creature that is two or more hexes away while using the Hide in Shadows spell.
Ineffective Hide
If a thief's hide level is very low compared to the level of the creature(s) he/she is stalking, the thief will be seen outright as if he/she did not even have the hide spell cast.
"Blinking"
If the thief's hide level is almost high enough but not quite, the thief may be invisible to the creature for a time, but eventually the thief will "blink" or appear to the creature for one round.
Calculation
Hide Level can be calculated by adding together the Character Level and Magic Level of a thief.
For example, a Level 7 Thief who is an Opener of Ways (Level 5 Magic) has a Hide Level of 12 (7+5=12)
Tips
Thieves with a Hide Level of 26 or more can hide from the drake in Axe Glacier.