Kingdoms & Lords

To defeat the Stygian Witches, you need to win 3 sets of 3 fights against their armies for a total of 9 fights.

Tips:
If you already unlocked (or bought) a stronger version of the unit I recommend, use that one.
Upgrade your units in the Training field. Each unit has 7 different skills. 6 skills cost coins and resources, the 7th costs diamonds. (Diamonds are a rare resource, spend them wisely.)
Magic cards, especially Flame strike, can help you a lot.
Mona or the Evil Monk can help you too, replace a unit with her/him.

Reminder:
Enemy with green up arrow means you do more damage.
Enemy with red down arrow means you do less damage.
Enemy with no arrow (unit icon instead) means you do normal damage.

1st set:
1st fight: (17 energy)
Stygian Witches:
- 2x True Knight
- 1x Heavy Halberdier
You:
- 3x Death Dealer
- 1x Fire Archer

2nd fight: (17 energy)
Stygian Witches:
- 1x True Knight
- 1x Heavy Halberdier
- 1x Warrior
- 1x Fire Archer
You:
- 3x Death Dealer
- 2x Armored Catapult

3rd fight: (19 energy)
Stygian Witches:
- 1x Heavy Axeman
- 2x True Knight
- 1x Gold Cannoneer
- 1x Armored Catapult
You:
- 3x Fire Archer
- 2x Heavy Halberdier

2nd set:
1st fight: (18 energy)
Stygian Witches:
- 1x Heavy Halberdier
- 2x Death Dealer
You:
- 4x Light Bringer

2nd fight: (18 energy)
Stygian Witches:
- 1x Warrior
- 2x Death Dealer
- 1x Gold Cannoneer
You:
- 3x Light Bringer
- 2x Fire Archer

3rd fight: (19 energy)
Stygian Witches:
- 2x True Knight
- 2x Death Dealer
You:
- 3x Death Dealer
- 2x Light Bringer

3rd set:
1st fight: (19 energy)
Stygian Witches:
- 1x Destroyer
- 1x Death Dealer
- 1x True Knight
You:
- 4x Marksman

2nd fight: (19 energy)
Stygian Witches:
- 1x Warrior
- 1x Paladin
- 2x Destroyer
You:
- 3x Warrior
- 2x Marksman

3rd fight: (22 energy)
Stygian Witches:
- 1x True Knight
- 1x Warrior
- 2x Destroyer
- 1x Death Dealer
You:
- 3x Marksman
- 2x Heavy Halberdier


Note:
Lots of different combinations of units can work just as well and you can use whichever you see fit. This guide is only here to help anyone who is stuck on a specific fight.