Talk:Monster Girl Encyclopedia World Guide III: Sabbath Grimoire/@comment-37532776-20190509180525/@comment-10429980-20190510025703

Just to clarify the above, mana markers don't involve ink. Its described as a spell that condenses mana and stabilizes it so it can remain in one spot for an extended time without dissipating. Mana markers tend to still be invisible, but the condensed mana means they can still be easily sensed (at least by those the marker is set to be sensed by). Their main purpose is to act as beacons, but advanced casters can include messages or other spell effects that can be used by the intended target.

Also, most monsters don't care all that much about money. If they work then its often for fun or personal satisfaction.