* Destructive Ray - reduces the defense of the desired unit by 3 points (on Advanced difficulty - by 4, on Expert difficulty - by 5). This is the only spell from the list whose effect lasts until the end of the battle or until the Remove Curse spell is cast.
The simplest and most straightforward modifier of the four. Because if luck triggers during an attack, the unit deals additional damage equal to the base damage D(bas) determined for that round of combat. It is clear that if a spell like Bless is cast on a unit, the damage from luck will be equal to (Dmax+1).
* Blessing - all units deal a fixed base damage equal to Dmax [or Dmax+1 with Advanced/Expert magic].
Clearly copied from the documentation.