"Recovers a knocked-out ally with around 33% of HP. The ally is immune to damage on that turn."
Cost: 7 MP
Source: Natalie - Unlocked at the world map after defeating ten magicos and having seven affection with Natalie.
Salvation is a spell that recovers a knocked out ally with one third of their health and makes them immune to damage for the rest of that turn.
This is an extremely useful spell, far superior to Fairy's Dust. The standard knock out recovery item typically leaves an ally extremely susceptible to getting knocked out again immediately, being brought back with only 1 HP and possibly with enemies still to use their skills for the turn. Salvation guarantees they won't be knocked out again immediately on this turn, and the 33% health is a buffer that could allow them to suffer another hit the next turn if the enemy is faster than the heal coming out, especially if they Guard.