Islands of Secrets

Level up Ingyr

But I leveled up Lianna first. Here's why:
1. When we first meet Lianna and Ingyr, Lianna has the "Magic Arrow" spell in her spellbook, while Ingyr doesn't. And this spell is very much needed in the early weeks of this map.
2. Lianna receives a bonus at the start of the game (for example, the "Domination" spell). You can still transfer Dark Priests, but you can't transfer a spell.
3. Ingyr has a weak ability (enhancing the "Lizard's Bite" skill). To be precise, the ability might be okay, but among other units, I prefer Beasts and Furies. They are easier to manage. Lianna has a better ability.
4. On this map, there is a quest for Lianna in "Ancient Evil" (for 30 crystals, you can get a level increase for the Dragon Daughter of Malassa).
5. On the last map, there is a quest for a level increase that can be completed by either Aeron or Lianna.

There is a Mentor on the map, plenty of chests, and almost every other week is a Creature Week. So, you will always have time to level up Lianna and Ingyr.

Added 6 minutes later
Damn, how do I beat "Ancient Evil" on Veteran or Hero difficulty?! These crazy demons invade me in the second or third week... On "Warrior" difficulty, they don't go beyond the outpost.