Big Tip: How to level new units

[ZirePhoenix]

The best way to level up a new unit is to pick it up at home, and use it to kill something else. The "Focus" button swings your picked up "thing" when you are near them. It works on regular maps too, but more dangerous as new units are slow and weak and enemies go for them.

[Addol]

Killing friendly units in early game is not that good IMHO. Each time you kill a friendly unit you get 1 DARK point and the phantom with DARK points might kill your friends when you're outside, so more units to heal and early game (if you don't use Scrabbit trick) you're really short on money.

Just focus on Ash, Witch and create a Valk/Warrior instead of Soldier.

About DARK points:
At 100 points you unlock "Blsphm" Title with Dark Eboreus skill.

[Amagi]

The failure trick is still the best imo, relatively safe and quite fast (early on at least).

[Fel]

if you need to rapidly level a new unit but already have good ones, there are a few ways to do it.

If you have some OP weapons (no matter if it's the right mana type, but it needs to boost at least speed, precision and the attack stat it uses for the 0 cost), a high level failure dungeon with few enemies but a lt of map props (preferably a type that is weak to the 0 mana attack the OP weapon has, so not a rock type for physical attacks for example), summon the new character in a prop and have it destroy the other props for massive exp (because they are high levels, and usually good modifier titles).

If you don't quite have this, the "normal" failure dungeon strategy (summon in a prop, beat the map) works well.

Alternatively, if you have a character that's powerful enough, you can have that character equip the one you need to power level and use him/her as a weapon, as both get experience.
Usually though, your weapons are more powerful than your unarmed characters, but I do use this for the "tutorial" levels by having ash equip marona to give a few first levels to her early on (she tends to lag behind in the first parts of the game, so getting here ahead from the start is usually a good way to make her useful even on the early chapters).