Strengths:
Excellent 7thlevel troop with complete Magic immunity
Two shooters and three flyers
Harpy Hags special

Weaknesses:
Gold troubles in early game.
Quite low HPs overall.

Army evaluation:
Troglodytes 4/3/5/1-3/4/50, immune to Blind
Infernal troglodytes 5/4/6/1-3/5/65, immune to Blind
Those little ugly things make a good cannonfodder for castle defenses, but I wouldn't take them into battle unless needed.

Harpies 6/5/14/1-4/6/130, return after attack
Harpy Hags 6/6/14/1-4/9/190, return after attack, no retaliation
Probably the best 2ndlevel unit in the game - upgraded version, of course. With their high speed, they can sit out of enemy walkers' range, dive at some shooters, score damage and return back home - an excellent army for capturing castles. Unfortunately, the AI knows that and will target them often.

Beholders 9/7/22/3-5/5/250, no melee penalty
Evil Eyes 10/8/22/3-5/7/280, no melee penalty
A potent shooter, should be the mainstay of your army.

Medusas 9/9/25/6-8/5/300, petrifying attack, no melee penalty
Medusa Queens 10/10/30/6-8/6/330, petrifying attack, no melee penalty
With upgrade, they're excellent castle defender and also with their close combat special they needn't any strong protection.

Minotaurs 14/12/50/12-20/6/500, good morale
Minotaur Kings 15/15/50/12-20/8/575. good morale
These big ugly guys should be used for crippling strong enemies. In most cases of a dungeon attacked, they were the only stack to stay alive after battle (and usually with little losses).

Manticores 15/13/80/14-20/7/850
Scorpicores 16/14/80/14-20/11/1050, petrifying attack
This strong flyer is excellent for attacking enemy shooters, as it be out of their range before the attack. The upgrade is excellent, the special helps them to survive at the enemy's end of battle field (often the petrified stack blocks further attacks.)

Red Dragons 19/19/180/40-50/11/2500+1s, 1-4 spell imunity, two-hex attack
Black Dragons 25/25/300/40-50/15/4000+2s, spell imunity, tow-hex attack, 150% damage to giants and titans
I guess nothing needs to be said about the black dragons - they're still the good old dragons they used to be. The reds, however, are considerably weak and should be upgraded ASAP.

Upgrading priorities:

• Infernal Troglodytes: Lower. In high numbers however, they make excellent castle defenses and upgrade increases HPs by 20%.
• Harpy Hags: Highest, for the speed and non-retaliated attack.
• Evil Eyes: Moderate, for the +2 speed.
• Medusa Queens: High, eight shots instead of four, also HPs and speed.
• Minotaur kings: Moderate, unless you want them to be main strike force.
• Scorpicores: High for +4 speed. They're a bit weak, though, so don't use them against enemy 6thlevels.
• Black Dragons: Top, +30% damage, effectively doubled durability, +4 speed.

Castle building in the first week:
4000g + 10o + 10g

Day 1:	Town Hall	2500g
Day 2:	Harpy Loft	1000g
Day 3:	Pillar of eyes	1000g + 1wogcsm
Day 4:	Chapel of Stilled Voices	2000 g + 5w + 10o
Day 5a:	Manticore Lair	5000g + 5w + 5o + 5m + 5s
Day 6a:	Labyrinth
Day 5b:	Upg. Harpy Loft	1000g + 2c + 2s
Day 6b:	Upg. Pillar	1000g + 1wogcsm
Day 7:	Citadel	2500g + 5o

Warren as 1stlevel dwelling assumed present. If it's not present, we don't go for Labyrinth.
The a) variant is for gold-rich scenarios, where you start exploring with a strong force in the second week.
The b) variant is for those scenarios where you've got no extra sources of gold - no chests, no mills, nothing. It allows you to start exploring with lots of Harpy Hags and pack of Evil Eyes, while you've got some gold left to build City Hall and possibly Manticore Lair and Labyrinth in second week.

Resource summary:
For a) variant, you'll need 11w, 30o and 18000g, which leaves us (20000 + 7000 - 18000) = 9000g for Day 1 to spend on troops. That is not much, because we surely want to upgrade harpies on day1 in second week (another 1000 down). 20x170 for harpies is 3400, therefore we have just enough to purchase five manticores as the only fighters. [And there's the ore requirement to fulfill in order to get Labyrinth and Citadel!]
In the b) variant, you'll need 7w, 18o and 11000g, which leaves 16000 on day1. From that, you can get all the harpy hags (3400), all the evil eyes (4760) and you can build mage guild and get a spell book. [Assuming an Overlord hero - Lorelei with Harpies special is best here, along with Logistics-proficient Gunnar!]
You'll still have enough gold left to buy Blacksmith, Marketplace, CityHall and Manticore Lair in second week. (And with some luck, Castle, too, or Labyrinth). Or, if you don't hurry on Manticores, you can recruit the ten Medusas (or wait for day2 and upgrade of Chapel).

Second week strategies: There's only one important issue: gold. Before buying all out troops, remember that you'll need a total of 8500 gold to raise City Hall. And believe me, it's foolish to wait five days till you accumulate the 5000 for the CityHall, if it could have been built for these five days (and earn you extra 5000 by this time). Unless you MUST conquer some important locations (ore/sulfur/wood/another village), try to make sure that you'll have that 5000 ready to build CityHall pretty quickly.

Troops cost weekly (with castle):
Without 7th level: 19525
With 7th level: 27525
With one castle producing 14000/week, it's hard to pick one or two armies that won't be used... but most probably it'll be trogs AND scorpicores, yet you may need the latter against shooters and will have to do without minotaurs. Capitol at 28000/week will solve your worries.
HPs grown weekly 1602 (plus 600 in blackdragons) at 12.18 g/HP (12.50)

Benefits:

• Academy of Battle Scholars: Seems better than just adding a point to a primary skill - because you get a secondary upgrade, too. Worth it.
• Artifact Merchants: Dungeon version of Black Market. If you can spare the gold, get it - usually later in the game.
• Blacksmith: Provides ballista war machines.
• Mana Vortex: Doubled spellpoints are fine for starting long journeys, but their best effect is for defending newbies that can do better with Slow/Haste/Dispel against enemy armies. Great benefit, indeed. However, works only once a week, on the first hero that enters the castle - so be careful to not waste it on a scout.
• Portal of Summoning: If you manage to flag only highlevel dwellings, this portal is great.
• Resource Silo: Sulfur producer
• Mushroom Rings: Increases growth of troglodytes. Buy soon to get some defensive reserves.

Strategy
Since wood consumption isn't any high (7 or 11), you'll need to capture a sawmill somewhere at the end of week1, maybe in week2. (or pick up one or two piles of wood somewhere.)
Be careful, if you build Manticore Lair and Labyrinth in first week, to have enough gold at hand. For the sake of City Hall, I would even sacrifice two or three treasure chests for gold instead of experience. [Especially those that offer 1000g/500exp, those should be used for experience only when badly needed!]

Forces combination:
I usually leave trogs and minotaurs unpurchased home, while HarpyHags, Evil Eyes, Medusa Queens and Scorpicores are the expeditionary forces (at least until dragons are available).
Note, however, that Minotaurs are VERY strong battle unit. So, to correct the above statement, I leave the minotaurs unpurchased home until I raise enough funds to purchase them... I prefer to get scorpicores sooner, because minotaurs are far less useful in capturing castles or fighting shooters.
The medusas are pretty good at castle defenses, too.

Heroes:
Overlords are pretty good. I suggest Gunnar as a special mover (with Logistics given and 5% bonus per level to it.) Arlach is an Artillery expert (which also means that he has a Ballista at start, so he's pretty good especially for the early exploration.) Damacom (which yeilds gold) makes a good secondary. All others increase A/D of some dungeon unit, so pick a hero according to the armis you're gonna like the most.
Among Warlocks, I recommend Deemer with MeteorShower as the best pick, followed by Darkstorn with StoneSkin and Malekith for Sorcery. Sephinroth (+1 Crystal) is a good secondary. Others seem dull to me.

Skills important for the troops and strategy:
With two shooters and three flyers, you should go for Offense and maybe Archery.
Ballistics and Armorer are good only to decrease the losses that you'll take.
Tactics is strongly recommended as it allows you to have first strike with Harpy Hags and Scorpicores with a chance to pick targets.

Unit	A	D	HP	Dmg	Sp	$$	AdjD	Dm/g	grow	weekD
Infernal trogs	5	4	6	1-3	5	65	1.80	2.77	35	63
Harpy Hags	6	6	14	1-4	9	190	2.30	1.21	16	37
Evil Eyes	10	8	22	3-5	7	280	4	1.43	14	56
Medusa Queens	10	10	30	6-8	6	330	7	2.12	8	56
Minotaur Kings	15	15	50	12-20	8	575	20	3.48	6	120
Scorpicores	16	14	80	14-20	11	1050	22.10	2.10	4	88
Black Dragons	25	25	300	40-50	15	4000	78.75	1.97	2	158