Isandrim

Isandrim (singular: Isandros) are a type/race of angel I created so that I can do whatever I want with them, and also so that if Andras interacts with other angel characters any differences can be explained by him being a different type of angel.

[Everything I say about angels here are my own ideas.  Some may be based on other things, but nothing here is meant to reflect any religious beliefs]

Isandrim are the "youngest" of the angels, being the last to be created.  They are also the least powerful, and the most human-like, although they predate humans.  [Angel headcanon: angelic language can't be understood or learned by humans, and may not even sound like language to humans, so the names of individual angels, and the names of "types" of angels, are not their "true" names; they're just the names used when communicating with humans; this includes the name isandrim].  There is a theory that isandrim were essentially "practice" for humans, but it's not known whether this is true (the reason isandrim resemble humans is purposely left ambiguous).

Appearance
Isandrim resemble humans, except for the wings and pointed ears, which can be short or long.  They can have all the same skin-tones, hair colors/textures, and eye colors that humans have, with the addition of white and gray hair which isandrim can be born with.

Isandrim can have up to six wings.  Most isandrim have two sets of wings on their back.  The larger, primary wings do most of the work in flight, while the slightly smaller, secondary wings, placed just below the primary wings, act similarly to a rudder or a bird's tail, aiding in turning and balance. Isandrim with a single pair of wings are less common.  These wings are larger than the primary wings on a four-winged isandros.  Some isandrim have a single pair of large wings on their back, and a second set of much smaller wings on their head which are mostly just decorative.  These head-wings are somewhat rare.  Six wings are even more rare.  The wings can be any color, though black and pure white are rare.  It's most common for the wings to be white on the top and back, with the rest being some other color, usually with markings such as stripes or spots.  It's also rare for the wings to lack any white at all.  However, a fallen isandros will shed their original feathers, losing all white and the color being replaced with something darker, while any markings are replaced with dark markings that resemble burn marks.

Other Info

• Isandrim are the least powerful of angels, the bottom of the angelic hierarchy, and they aren't actually immortal.  But they do have very long lifespans, in millions, maybe billions, of years.  They can be killed, but it's very difficult, and usually can only be done by a demon or another angel.
• They can reproduce the same way as humans, although do so very rarely.  Since they have such long lifespans, they don't really need to reproduce very often, and they have very low fertility.  They can't produce offspring with humans or any other species, so there are no hybrids.
• It takes about 2000 years for an isandros to reach full maturity.  They are about equivalent to human teenagers at around 1000 years.  Although they continue to age at a very slow pace after reaching maturity, they will eventually stop aging so they always look young.
• Since isandrim don't reproduce often, they don't really have a formal education system, since there are rarely more than a few children at any one time (and often there are no children, or only one), so they are mainly taught by their parents.  
• It’s pretty rare for isandrim to interact with other angels.  They have their own systems in place, and only consult the older, more powerful angels if they run into some problem they can’t fix themselves.  Since they're quite a bit different from other angels, they prefer to keep themselves isolated.
• Part of the culture of isandrim is that they practically worship archangels (they just don't call it that) and treat them almost like gods.  It's considered akin to blasphemy (again, they don't call it that, but that's how they treat it) for an isandros to speak directly to an archangel, and they're not even supposed to be in an archangel's presence.  If they need to communicate with an archangel for any reason, they will do so using a messenger (usually an angel that is slightly higher in the hierarchy than the isandrim themselves are).  This is entirely self-imposed, and how the archangels actually feel about and treat isandrim depends entirely on the individual.
• Many isandrim are guardian angels and soldiers.  Being similar to humans makes them ideal for the former–although other angels may be assigned to the role–and the latter is because they’re typically used in less important battles, like the little skirmishes that are sometimes still instigated by certain groups of demons.  Of course other angels might sometimes get involved, but isandrim are typically considered less important and more disposable (that is to say other angels tend to think of them as more disposable/less important).