By drinking this pitch black fluid, you will gain a very special notebook that can change reality.
*First, you must choose a theme to this notebook, it will define it's powers and limits, it can be the classical Death Note that can kill anyone, a Love Note that makes people fall in love, a "Waifu" note that can turn anyone into cute girls and etc.
*Your Note can achive any sort of effects and details if it's in the theme, the previous mentioned Love Note for example would be able to make the most unlikely couples easily and even detail how it would happen, Notes that make larger changes in reality can also reshape the memories and mind of others to make them see any changes as normal.
*You can summon you Note to your hand at will, restoring it from any damage making it imposible to destroy or steal it from you, but others can still use it.
*For convenience sake you also can summon a pen with infinite ink.
*Your Note's pages are infinite never running out.
*If you wish, you can gain a Note Spirit to follow you around, their form and personality would be based on your Note themes, they will be frendly if posible or at least not dangerous and amoying at least, they would be invisible to everyone execpt you but can make other people able to see them by letting them touch your Note.
*If you wish, you can also put "rules" on your Note, you would be able to ignore any of these rules at will but any other person who used your Note would have to obey them, these rules can come with punishments but only stuff that fits with your Notes theme. A Love Note would not be able to directly kill you, but it could destroy your relationships.
*You gain "Shinigami eyes" for free, those give you a usefull power that helps in the use of your Note, like eyes that can see peoples names floating over their heads or photos, eyes that can see someone's true love or etc.