Fiendish Glare vs an Invisible Creature currently outlined by Glitterdust?

Question

A creature cast invisibility on itself. We successfully covered it with glitterdust. Can our Warlock/Acolyte of the Skin target the outlined creature with his Fiendish Glare? The source of uncertainty is that Fiendish Glare requires that he "see" the target. We can't see the invisible creature, just its outline.

Fiendish Glare:

An acolyte of the skin has the supernatural ability to unnerve opponents with a ferocious glare once per day. This is not a gaze attack, and the target need not meet the acolyte's eyes or even see the acolyte (although the acolyte must have line of effect to the target). Glaring is a standard action that affects any creature the acolyte can see within 100 feet. The target becomes shaken for 10 minutes

Glitterdust:

A cloud of golden particles covers everyone and everything in the area, causing creatures to become blinded and visibly outlining invisible things for the duration of the spell.

Answer 1

Yes, visibly outlining a creature makes it visible

Basically the question is whether "visibly outlining invisible things" makes them visible.

While this is assumed in most statements about Glitterdust it is not explicitly said in the spell.

The similar spell Fearie Fire explicitly states

A pale glow surrounds and outlines the subjects. Outlined subjects shed light as candles. Outlined creatures do not benefit from the concealment normally provided by darkness (though a 2nd-level or higher magical darkness effect functions normally), blur, displacement, invisibility, or similar effects. PHB, p.229

This wording could descibe a feature specific to Fearie Fire but also a general effect. I would judge, yes, the creature is visible and thus a valid target for Fiendish Glare.

Answer 2

This DM would rule that the acolyte can use fiendish glare on the invisible but glitterdusted target

This DM would rule that a creature that is invisible yet that's been the victim of the 2nd-level Sor/Wiz spell glitterdust [conj] (Player's Handbook 182) is, in fact, visible enough to be the target of spells and abilities that require the spell's caster or the ability's user to see the target. (This reader has always assumed that's kind of what else the glitterdust spell is for!)

To be clear, while a target's outline isn't technically the target, the Player's Handbook on Target or Targets says, "You must be able to see or touch the target, and you must specifically choose that target" (175), and for this DM being outlined by the effect of a glitterdust spell would allow a caster to meet both those requirements.

This DM does not, for example, require a caster to see a creature's face (or what passes for one) for a creature to be counted as visible enough to be a target of an effect that has an entry like Target: 1 creature. Just knowing the creature's precise location is sufficient for this DM, and glitterdust makes a target's precise location known.