I've been playing as the Sidar, and so far I'm liking them. Now I'm wondering what the best way to acquire shades as a builder is. I know you can send out units to fight until they're high enough to make into shades, but is there any way to get to level 6 without relying heavily on combat? Can you make shades as a mostly peaceful builder?

Spellcasters get free xp.....

Spellcasters get free xp.....

Druids get it a lot faster. Unfortunately you can only have three of them at once.

Also heroes get free XP. So building kithra kyriel is really the same as saying that 26 turns later you'll get a free GP, if you want one.

I used the shadows from the council of essus to make 6th level units while remaining at peace. I did it so much that some of my "friend" his cities felt to the barbarians, because all defenders where gone. Thought they had no clue I was behind it, I was still one of their best friends :)

Shadows there ability to briefly become hidden nationality and then normal again helps a lot; shadows are also invisible and attack the weakest member of a stack.

A thought would be to go for Divine units with high levels of Altar of the Luonnotar. Then you get a nice amount of base XP along with some XP gain.

It's tough changing in lvl 6 mages and conjurers I'm finding out...very tough decision.

Its tough changing anything lvl 6. I keep waging war and keeping my great champions and then having to disband them and going back to nearly promotionless army that has a hard time standard up to the larger armies fielded by the AI. Of course obtaining Orthus' Axe or an early Rathus with his Nether Blade goes a long way.

As i've mentioned before, and as kolpo pointed out, shadows really are your friend here. completely hidden, hidden nationality, marksman and a high base attack, what more could you ask for? you can go from shadow to shade in 20 turns max. which basically means +12 hammers and +9 breakers added every 20 turns once you get the right wonders running (which you should beeline for by the way)

In my first game with the Sidar I realized that it is quite difficult to get a horde of schades...

Here are my conclusions:

1. The larger the map, the more fights there will be...so increase the map size.

2. Barbs are an excellent way of getting cheap xp.

In my current game i decide to go for raging barbs with 1 AI less than normal...it was tough at the beginning, but on turn 100 I already had about 6 shades :)

Ok, I still have only my capital, but with Axeman i slowly start to expand...

Well, according to the changelog, if something has a CHANCE of going Barbarian, and you disband it, then it instantly goes Barbarian.

So get a Conjurer with Chaos II, summon, disband, and gain exp. Can be somewhat slow, but at least it gets you a steady source of exp without too much risk (be sure not to summon while in a town though, or the Chaos Marauder gets the weapon promotions and it becomes a bit harder to win safely)

So far I've noticed a few ways:

Altars and disciple units will work, if you convert to good via the Order or Empyrean (you can always switch back to CoE I believe, FoL or RoK and remain good). They also have other benefits, like tying into the natural Builder victory condition :)
Shadows and your "friends" is great if you don't mind being sneaky :)
The Assassins' Guild (forget the actual name), which ties into the above if you use Ghosts and a bit of Esus-worship, boosts starting xp for recon units.
Worshipping Esus will grant your units in general, and particularly your recon units, the ability to gain xp from your neighbours.
Obvious things like apprenticeship and Form of the Titan also help.
Barbs are good sources - keep a lair going somewhere or even a barb city, or just an area of wilderness, and send your shades-to-be to wait for the barbs to appear.
As xienwolf noted, disbanding units with Enraged can create a source of barbs. Chaos Warriors are good, or you can use Lunatics and the like if you're OO. Chaos Mana will occasionally throw them up through mutation as well I believe.
Magic users gain xp completely passively, and adepts aren't pricey, but it's not as quick as the other methods. In the meantime, give them Shadow promos and you can use them to buff other units with hiding effects. Obviously heroes also gain xp like this, but I wouldn't recommend shading them very often :)
Capturing enemy units with levels via Inquisitors should work, but comes rather late. If you capture Enraged units from the Balseraphs or other OO followers you can even disband them and kill them again for double XP.
Lastly, you definitely want to be running a specialist economy. Farms everywhere (maybe not plains, but FPs and grass), seafood, Agriculture, beelined Sanitation for more grass and extra farm output, trade your duplicate health resources for happiness boosters and you're quids in. Beeline the specialist boosting wonders, especially Great Library. Caste System will let you assign loads of extra specialists.. There's also a civic which provides a flask and 3 culture per specialist or something. Republic IIRC. I found the happy cap was the biggest obstacle; spread religion and build temples (also allowing you to assign more specialists), grab happy resources and trade for them if you can (Esus is handy for keeping trading options open with lots of civs). Guardian of Nature could work, but another religion is probably more optimal. Most importantly, since you're on SE you don't care much about a low science rate and high gold rate - settle or capture a few more cities than you'd normally be able to afford and BUILD GAMBLING HOUSES. Their happiness boost in line with your gold rate ties in beautifully. The undercouncil can pass a resolution to reduce their cost, though I'm not convinced it works as intended.

Just a tidbit, but when settled as great merchants, shades give +1:food:. This gives them the capacity to have infinitley large cities, espescially with the Ashen Veil. Spam adepts and level them up, run sacrifice of the weak, and then stack the merchants.

Note: I haven't tried this, just thought of it now.

So far I've noticed a few ways:

Altars and disciple units will work, if you convert to good via the Order or Empyrean (you can always switch back to CoE I believe, FoL or RoK and remain good).

I'm pretty sure that Neutral players can build the altars just as easily as Good ones. Also, it seem that the Empyrean and CoE effect alignment like RoK and OO would; they don't seem to make you good or evil, only making Evil/Good civs Neutral. (I think I change it so they move you one step towards good/evil)

Just a tidbit, but when settled as great merchants, shades give +1:food:. This gives them the capacity to have infinitley large cities, espescially with the Ashen Veil. Spam adepts and level them up, run sacrifice of the weak, and then stack the merchants.

Note: I haven't tried this, just thought of it now.

In my current game I've been going mostly Sages and Engineers with the specialists I've gotten from cities. And now I'm going Great Merchants with the shades. I'm RoK now, and I just sacrificed Bambur and Artheindein for shades, and I'm gonna switch to OO and then Veil to get Hemah for some Vitalize and then as a shade, and Saverous will become a Shade as well. Then I will switch to Veil to maximize on specialists.

Haven't gotten CoE in this game since I didn't aim for it, and it doesn't seem like it has spread much.

You don't have to use farms in all cities since you probably won't produce many specialists in many other cities than your capital with all it's wonders (since your industrialist), or maybe 1 or 2 other cities.

go for council of esus and then armoured cavalry, if you have all the building upgrades in one city.(ride of 9 kings, hippodrome, stable, plus apinticeship, great comander's special building, and the statue of the titans) about 20 xp for new mounted unit.

im producing shadowrider every 5 turns; and then send them to get a little xp,

after playing this strategy i think that maybe gp should cost -1 food, (and perhaps put regular specealists at -1 food instead of -2) i think that could keep the sidar's shadows from being overdone. Im playing with 3 cities comerce culture and a military farm.

Yeah I figured that would be a good plan to late for this game, but I'm doing pretty decently for my first attempt. But I'm considering capturing the Khazad city which has Ride of Nine Kings just to try it out.

My capital got:

2 Free Sages (+14 Sci)
6 Great Sages (+60 Sci, +6 Hammers)
10 Great Merchants (+20 Sci, +70 Gold, +10 Food)
5 Great Engineers (+25 Hammers, +25 Sci)
+125 GPP/Turn atm with 11 Specialists running.And I still got Hemah and Saverous to add, and an Archmage I'm currently using for a while (it got Vitalize and some other goodies). And I got some more units around 20 xp.