Battle Guide:
Enemy Morale determines whether they will retreat. If you manage to lower it below 30, they will retreat for your victory.
Lowering Morale can be done with tactics(- up to 10), or with making enemies retreat with lower than around 50% HP(-3~4 or something), or defeating them (-10).
Every time enemy reinforcements come in, they boost morale by around 2. Similarly, if they defeat your units, they get a morale boost as well.
If enemy breaks down the door/gate, you will get a negative emotion from all factions.
If your unit retreats out of map or survive the battle, they will be back with full HP after the battle.
Destroyed buildings will not be recovered, and you need to rebuild them.
Even if your unit dies, you can easily recruit them once more, similarly you can recruit past units in NG+.
Unit List(Specials need to be unlocked with research):
Footman
Normal: When situated at a place with a defense building, attack is boosted.
Special: Heals every turn.
Retreats at 50% HP when there is no defense building.
Knight
Normal: When situated at a place without a defense building, attack and number of attacks are boosted.
Special: When situated at a place without a defense building, 30% chance of reducing enemy number of attacks by 1(Stackable)
Retreats at 30% HP when there is no defense building.
Archer/Bowmen
Normal: Deals additional damage to knights and dragon riders
Special: When situated at a place with a defense building, 25% chance of reducing enemy number of attacks by 1(stackable).
Retreats at 50% HP when there is no defense building.
Unlocks tactics: Big Arrow - Deal Damage at a specified area.
Unlocks tactics: Spring Shower Rain of Arrows - Deal Damage to all enemies.
Musketeer
Normal: Additional damage to walking enemies, knights and dragon riders.
Special: When attacking, 30% chance to attack again(Stackable, up to 9 times).
Retreats at 50% HP when there is no defense building.
Mage/Wizard
Normal(More of description): High attack.
Special: When attacking, 50% chance to do 1.5 times the damage.
Retreats at 50% HP when there is no defense building.
Samurai
Normal: When fighting walking enemies, attack power increased.
Special: Number of attacks increased by 2.
Retreats at 10% HP when there is no defense building.
Rock Tosser
Normal: Deals additional damage to mechanical enemies.
Special: When attacking, deals damage to all enemies in the area.
Retreats at 50% HP if there is no defense building.
Unlocks tactics: Stone Toss - Deal damage to all enemies, allies and buildings in a specified area.
Unlocks tactics: Ice Toss - Deal damage to all enemies, allies and buildings in a specified area.
Dragon Knights
Normal: Ability to move while ignoring enemies other than dragon riders in the area
Special: When attacked, 25% chance to dodge enemy attack.
Retreats at 10% HP when there is no defense building
Civilian Soldiers
Normal: Repairs structure every turn.
Special: None
Retreats at 70% HP when there is no defense building.
Tactics: (For easy reference, money will be in units as seen in game)
All Power Up(50 units) - Boost attack and defense of all units for 5 turns
Attack Up (50 units) - Boost attack of all units for 5 turns (Requires Soldier tent)
Structure Defense Enhancement(50 units) - Boost defense of structures for 5 turns
Emergency Recovery (150 units) - Recover 30% HP of all units in a specific area (Requires Hygiene/Welfare Camp)
Door Repair(500 units) - Recover 300 HP of your door (Requires DOOR! DUH!!).
Ambush Attack(Snow) (50 units) - Deals damage to all enemies in areas where there is no building, traps etc(Requires Snow)
Ambush Attack(Field) (50 units) - Deals damage to all enemies in areas where there is no building, traps etc(Requires NO SNOW)
Rock/Castle Explosion (150 units) - Choose a Rock/Castle, that building is destroyed and large damage dealt to all allies and enemies in the area.(Requires Rock/Castle)
Follow-up attack on hole (30 units) - Enemies that fell into the hole takes a large damage(200) (Requires hole/pit)
Plain of Maze Attack follow-up attack (10 units) - Deal Damage to all enemies in Plains of Maze.(Requires Plain of Maze)
Bridge drop (20 units) - Bridge of selected area is destroyed, causing damage to enemy in that area.(Requires Bridge)
All Bridge Flushed (100 units) - All bridges are flushed away by a massive flood, dealing damage to all enemies in areas with bridges.
Stone Toss (30 units) - Choose one area to toss stones. Damage is done to all allies, enemies and structures. (Requires stone toss unit)
Ice Toss (50 units) - Choose one area to toss Ice. Damage is done to all allies, enemies and structures. (Requires stone toss unit and ice).
Big Arrow (70 units) - Choose one area, damage is done to all enemies units in that area. (Requires archer/bowmen)
Spring Shower Rain of Arrows(150 units) - Damage is done to all enemies units. (Requires archer/bowmen)
Lance of the dragon knight (230 units) - Choose one area. Dragon knights does a special attack to all enemies in that area (400++?). (Requires Dragon Knight)
Fake Intel (200units) - Reduces up to 10 enemy morale. The more enemies there are, the less effective.
Enemy Movement Interference (20 units) - Enemy movement is hindered at certain rates for 3 turns.
Retreat Negotiation (500 units) - (I am not too sure on this) After 20 turns, if the battle is still ongoing, you are considered to have won.
Recommended way to play, though you need several playthroughs to prepare the units and money to get them fast.
In NG+, before it starts, if possible, do the search that allows you to hire units at 50% cost.
The easiest way to win(So far, at least):
For all areas with 2 or more spaces, fill them with Knights.
Then place Large holes/pits there as well. Behind the 3 spaces area, place a Hygiene tent to enable heals. Behind the 2 spaced area near the front, place a soldier's camp to allow Attack Up tactic. Enemies should not get past your knights, so the camps should be safe.
Place some units like dragon knights etc at single area locations, or behind your door/gate. Personally I have 2 dragon knights with stone walls to block off the paths, or at least buy some time. And there is 2 Mages behind the door, and a footman(cause I can't think of what else to put). Mages are not entirely useless, they do a single large damage to one enemy. The door protects them, and their attack can do around 300~+ especially if skill is activated.
At the start of the battle, use "Enemy Movement Interference". This will likely make only 1 enemy move to where the knights are, if there is any.
Then use "All Power Up" the next turn. The knights should kill most units in a single turn, especially if they fell into the hole(60% chance of that)
Then use "Attack Up" to boost their damage further.
Go back to "Enemy Movement Interference".
Repeat process, heal if necessary. Their morale should drop rather drastically, so you may not even have to deal with some of the bosses!