You need to find a Realmic Transmutor in Nightingale if you want to activate a Minor card. These differ from Realm Cards, which are used to create different kinds of realms. Minor cards are instead used to change the rules of the current realm, so you can gain an advantage, depending on what you want to do.
One Minor card might increase your travel speed, while another might make certain enemies drop more loot, but there will often be a negative effect to balance out any benefit you gain. There are 50 Minor cards to discover in Nightingale currently, and I've listed the ones I've discovered below so you can make the most of the Realmic Transmutor in Nightingale.
