Ethergaunts: eldritch abominations from the ethereal plane, best known for their horrifying abilities and innate casting. They come in three colors, presented here in ascending level of power for convenience.
Red Ethergaunts have a mere 5 RHD. Their ability scores are interesting: everything gets a low +2/+4 bonus, except for intelligence which instead enjoys a +12 modifier. Many of their special abilities are shared with the other ethergaunts, so this is not a bad moment to go over those.
Firstly, there's Enslave: a 3/day Dominate Monster spell that can indefinitely enslave creatures (albeit with a new saving throw every day). The effect is also broken if the ethergaunt travels more than one mile away from its slave. Ethergaunts can have a number of enslaved creatures equal to their charisma bonus, meaning that the average NPC red can only have one, but a PC might obtain many more.
Stupefying Gaze is a gaze attack that deals 1d4 damage to all mental ability scores, with the ability to turn it on and off as a free action. It's not friendly, but positioning yourself 30 ft. away from your friends isn't too hard, and if you can't they're not hurt by it.
Immunity to Spells gives ethergaunts infinite spell resistance versus a number of arcane spells, depending on their rank. A red ethergaunt is immune to everything from 2nd level or lower, which isn't too impressive but not useless either. Note that it doesn't work versus divine magic.
All ethergaunts get EWP with the Etherblade, which is kind of like a greatsword except it has no expanded crit range and can shoot laser beams. The beams are unimpressive (1d6 damage, 40 ft. range increment, 50 unrestorable charges per weapon), but might be relevant in one or two situations.
Total Vision gives the ethergaunt some kind of not-quite-blindsight in a 40 ft. radius, which functions regardless of facial coverings and bypasses effects like stealth (even darkstalker stealth) and invisibility.
Finally, there's Material Jaunt, which allows an ethereal ethergaunt to shift to the material plane for 1 round/HD every hour. Most PCs will presumably be on the material by default, making this ability mostly useless.
On top of this, the red ethergaunt gets the casting ability of a 9th-level wizard (yes, you read that right).
What to rate a creature like this? The casting ability combined with the various useful traits (most notably Enslave) makes me suspect that +4 would still be too little: four levels of a prestige class, 1-2 more feats, and a familiar shouldn't outweigh great perception, 3/day Dominate Person, a much better casting stat, and immunity to some low-level magic. In the end, I'll go all the way up to +7: the giant bonuses simply require it.
Because many of the features introduced here are found again in the other ethergaunt subraces, I'll stop here for now and then do the white and black 'gaunts in a double update. Before rating those, I'm interested in seeing the community opinions here.