Greater Mark of Shadow
Source: Eberron: Forge of the Artificer p. 45
Prerequisite: 4th
You gain the following benefits.
Ability Score Increase. Increase one ability score of your choice by 1, to a maximum of 20.
Improved Intuition. When you use the Cunning Intuition benefit of your Mark of Shadow feat, you can roll dice:1d6|noform|noparens|avg (1d6) instead of dice:1d4|noform|noparens|avg (1d4).
Improved Shadow. When you use the Shape Shadows benefit of your Mark of Shadow feat to cast Invisibility without a spell slot, you cast the spell as its level 3 version.