Moving into slightly more Chaotic regions, we have the demons! First of them is the alkilith, a horrifying acid beast.
Alkiliths have 11 outsider RHD. Their stats are reasonable for a medium-sized creature (16/25/16/14/17/15), especially when you consider that with one more RHD they get a size increase to Large. +6 natural armor is a bit shabby, and four 1d8 slams are hardly the greatest natural weapons out there.
Special qualities are quite good: DR 15/good, immunity to acid, electricity, and poison, cold and fire resistance 10, and 100 ft. telepathy. They additionally get SR 23.
The alkilith also has some notable special attacks. Its slams all deal acid damage that continues for multiple turns, which would be pretty nifty if it didn't also risk destroying loot. Additionally, they can control nearby oozes (largely irrelevant at those levels, but flavorful), and get a 50%-probable hezrou summon per day.
Furthermore, alkiliths can assume the form of a toxic mist cloud (Gaseous Form that hits enveloped creatures with Cloudkill). Paradoxically, entering this form will probably make it more vulnerable to attack, as it loses its natural armor bonus and doesn't get extra DR (except against the rare Good non-magic attack). It's good as backup flight and offense, I guess.
Finally, there's some SLAs, and they're quite nifty. The 3/day abilities (Cone of Cold and Unholy Blight) are not all that impressive, but the at-will ones are varied and numerous (Contagion, Desecrate, Detect Magic, Dispel Magic, Enervation, Hold Monster, Magic Circle Against Good, Stinking Cloud, self-only Greater Teleport, Wall of Ice). Some of those are underwhelming for the level they're gained at, but others (Detect Magic, Hold Monster, Greater Teleport, Wall of Ice) definitely hold up.
On the one hand, the alkilith has a varied array of special abilities and a quite good chassis as well, especially with its size increased to Large. On the other hand, its magic abilities are not all that impressive, and I'm fairly sure it doesn't have hands (or, y'know, humanoid physiology of any kind).
+0 LA for now, interested in seeing the community's judgement.