Gremlin
GremlinHealth: 4Attack: 3Shots: noneMovement: ground
30 gold (16)Hex size: 1Defence: 3Dmg: 1-2Spd: 4 (extra slow)
Gremlins are only better than imps... cheap and plentiful too, but slow and weak in all aspects. If you have quite a lot of them, enemy may be very surprised how much damage gremlins can do. Upgrade is awesome.
 
Master Gremlin
Master GremlinHealth: 4Attack: 4Shots: 8Movement: ground
40 gold (16)Hex size: 1Defence: 4Dmg: 1-2Spd: 5 (slow)
Master gremlins are the only level one shooters (except for halflings in AB) and provide a great advantage in early stages of the game, thank god the gremlin rush desn't work anymore, it was unstoppable. Otherways, awesome upgrade, but keep the ammo cart handy, these guys have only 8 shots. They do have a hand-to-hand penalty, so try to block them.
 
Stone Gargoyle
Stone GargoyleHealth: 16Attack: 6Shots: noneMovement: flying
130 gold (9)Hex size: 1Defence: 6Dmg: 2-3Spd: 6 (swift)
Special: non-living.
Not a very good fighter, but quite useful for preventing enemy shooters from using their range attacks.
 
Obsidian Gargoyle
Obsidian GargoyleHealth: 16Attack: 7Shots: noneMovement: flying
160 gold (9)Hex size: 1Defence: 7Dmg: 2-3Spd: 9 (ultra swift)
Special: non-living.
30 Gold for 3 extra speed and 1 attack and defence... not a good upgrade, but makes them better shooter-blockers. I would prefer to save money for golems who will last a whole lot longer. Recruit gargoyles only when you are quite desperate for army.
 
Stone Golem
Stone GolemHealth: 30Attack: 7Shots: noneMovement: ground
150 gold (6)Hex size: 1Defence: 10Dmg: 4-5Spd: 3 (very slow)
Special: non-living, take 50% damage from spells.
Great town defenders because spells just don't take them that easy! Too slow for heroes though, that's what upgrade is for.
 
Iron Golem
Iron GolemHealth: 35Attack: 9Shots: noneMovement: ground
200 gold (6)Hex size: 1Defence: 10Dmg: 4-5Spd: 5 (slow)
Special: non-living, take 25% damage from spells.
Great upgrade! Speed is usable for hero armies while extra hit points and magic resistance make them even tougher. Only a foolish player will cast offensive spells on iron golems, only a quarter damage will get through. Iron golems are great to defend shooters.
 
Mage
MageHealth: 25Attack: 11Shots: 24Movement: ground
350 gold (4)Hex size: 1Defence: 8Dmg: 7-9Spd: 5 (slow)
Special: no hand-to hand penalty, hero spells cost -2 mana.
Good offensive shooters, but even though they suffer no hand-to-hand penalty, keep them defended because their hit points and defence are low. Spell bonus is great! Magic arrows cost 2 mana! Note that when all magi on the battlefield are dead, spell bonus disappears.
 
Arch Mage
Arch MageHealth: 30Attack: 12Shots: 24Movement: ground
450 gold (4)Hex size: 1Defence: 9Dmg: 7-9Spd: 7 (extra swift)
Special: no hand-to hand penalty, hero spells cost -2 mana, no penalty for shooting through seige walls.
Reasonable upgrade adds speed, improves defensive ratings and wall penetration will decrease the range penalty in seige attacks.
 
Genie
GenieHealth: 40Attack: 12Shots: noneMovement: flying
550 gold (3)Hex size: 1Defence: 12Dmg: 13-16Spd: 7 (extra swift)
Special: 150% damage to efreet.
Offensive unit with big lack of hit points, do not attack unless it will destroy the target. I would prefer 1 naga instead of 2 genies.
 
Master Genie
Master GenieHealth: 40Attack: 12Shots: noneMovement: flying
600 gold (3)Hex size: 1Defence: 12Dmg: 13-16Spd: 11 (quick)
Special: 150% damage to efreet, can cast random beneficial spells on allied stacks with spell power of 6 at advanced spell level (spells are not totally ridiculously chosen though, ex: will not cast prot. from water when fighting wandering creatures).
Master genies are a totally different story with their spellcasting abbilities. If you have room in your army, split master genies in many stacks to be able to cast more beneficial spells on your units per turn. Remember that most of their spells last for 6 turns and that a single unit stack can have a maximum of 3 spells affecting it. Great upgrade for 50 extra gold.
 
Naga
NagaHealth: 110Attack: 16Shots: noneMovement: ground
1100 gold (2)Hex size: 2Defence: 13Dmg: 20Spd: 5 (slow)
Special: no enemy retaliation.
Nagas and naga queens are necromancer's black and dread knights' toughest competitors for the first place amongst the level 6 units. Nothing to comment really, this unit is great all around, just don't bother blessing or cursing that great constant damage.
 
Naga Queen
Naga QueenHealth: 110Attack: 16Shots: noneMovement: ground
1600 gold (2)Hex size: 2Defence: 13Dmg: 30Spd: 7 (extra swift)
Special: no enemy retaliation.
Extra speed and extra 50% of that constant damage are worth the extra 500 gold that make naga queen the most expensive in level 6.
 
Giant
GiantHealth: 150Attack: 19Shots: noneMovement: ground
2000g+1ge (1)Hex size: 1Defence: 16Dmg: 40-60Spd: 7 (extra swift)
Special: immune to mind-affecting spells.
Their damage is great, especially if blessed. Their dwelling is really cheap compared to other level 7 dwellings. The only drawback is the gem cost. Anyway, a good unit to recruit and upgrade later in the game. Nagas and giants make a hardly beatable ground attack force.
 
Titan
TitanHealth: 300Attack: 24Shots: 24Movement: ground
5000g+2ge (1)Hex size: 1Defence: 24Dmg: 40-60Spd: 11 (ultra quick)
Special: immune to mind-affecting spells, no hand-to-hand penalty, do 150% damage to black dragons.
The best shooter in the game and the most expensive level 7 unit. Shooting abbility is great, as well as twice the hit points and major increases in speed/attack/defence, but the price is more than doubled... This is really an endgame creature because the dwelling costs 25000 gold and 30 gems to upgrade and the titans are so expensive too. Still useful to bless them. If you see some black dragons on a distance, shoot them for that extra damage with no retaliation.