Rune Assassin

Rune Assassins are human Fighter/Thieves who work as assassins in the service of a cabal known as the Twisted Rune. They act as agents and enforcers for the Twisted Rune's various schemes, and as such Gorion's Ward and party may encounter them at multiple points during their adventures in Athkatla, if their paths happen to cross with those of the Twisted Rune.
==Combat==
As a variant of the common Thief class, Rune Assassins use the same basic tactics as thieves; at first opportunity, they will use Hide in Shadows, a Potion of Invisibility, or their undroppable Sandthief's Ring to enter stealth mode, setting them up for a Backstab attack. They are not especially durable, but they can inflict considerable damage if they successfully pull off their Backstab. They can also see the invisible and have various immunities (follow the link for their ring for more details).
==Mod content==
The Sword Coast Stratagems mod revises these creatures. A SCS Thief AI script is assigned for smarter tactical behavior, threat recognition and opponent vulnerability assessment logic. The Fighter/Thief is now a kitted Assassin. Weapon proficiency is changed to just one pip in short sword, as well as one pip in single weapon fighting style (which boost AC by 1 and critical hits on a 19). Not only that, but the target selection determined by the script looks for vulnerable party members - examples include: those with no stoneskins, those with no helmet critical hit protection, those not protected against magical weapons, and especially mages.
The Assassin has the following special assigned abilities and effects: Sees invisible creatures by script, starts the battle invisible, gets +1 THAC0 and +1 extra damage. The Assassin can use and will use the Poison Weapon kit innate ability in combat. The potion of speed will be used to provide 4 Attacks per round. If damaged over 50% the Potion of Extra Healing will be consumed. The thief can apply normal invisibility as required each round. In addition to this, the creature has SCS random treasures in their inventory.
More Rune Assassins are encountered in the Azengaard mod.
Several additional enemy Rune Assassin guardians are summoned in the Twisted Rune Hideout if you are playing the Tactics for BG2EE mod.