Summon Spirit - This spell summons a shade from the netherworld to fight on your side. This is a pretty useless spell, because shades are very weak monsters. Also, the shade disappears after a while. You can buy this spell in Pergies, from the same guy that sells you the Minor Manna spell. Here's what it does.
Some walls are old, cracked, or moldy.
These walls are often flimsy enough to simply knock down with this spell. There are lots of places where this spell is useful, including the Agate Tower. You can buy this spell from Paulo, in Pergies, too. Or, you can do a mission for him. This spell has a chance of making monsters that previously wanted to kill you actually fight on your side.