Order of the Library

Whilst other bloodhunters rely heavily on their magics and mutagens, Those who follow the Order of the library, or librarians, bear testament to their skill and knowledge, even without their accursed blood. Librarians bear within their blood infinite and accursed knowledge, and specify in a slow, informed hunt. field research and study allow them to always make the right decision when entering a fight.

Walking Library

Starting at 3rd level when you enroll in this order, your blood holds secrets, bound to your blood you may take notes of whatever knowledge you gain of a creature (sorted to resistances, weaknesses, attacks, individual stat scores, languages, spells, and features) any trait you escribe into your blood can be remembered as a bonus action without need of a history check, but information is remembered from the last monster, not the one in front of you (DMs this just means that if you make a special beholder who has more spells, the player won't know them). Even modify memory cannot remove this information, only 'wish' or a similar power.

Field study

Starting at 7th level, you may fiddle with a creatures corpse to determine facts about it, and remember them through 'walking library'. simply spend 3 minutes testing them, and in the end roll History (intelligence), gain the following info about the creature. This cannot be repeated on the same creature.

>5 - learn a creature's hit die and resistances

>10 - learn a creature's at5tack roll and damage type

>15 - learn a creature's potential spell level (but not individual spells)

>20 - learn a creatures STR, DEX, CON, CHR, INT, or WIS

>30 - learn a creature's entire stat block.

Learn on the fly

at 11th level, your blood quickly gathers information about a creature. whenever you observe a creature making an attack, as a reaction, make an INT save against the creature's 10 + the creature's INT + the creature's DEX. if you succeed on this save 3 times, the attack in question has disadvantage to hit you. If you see someone fail to meet a creature's armor class 3 times, gain advantage against said creature. This applies to other identical creatures, and you lose that advantage on a long rest. 

Spread the knowledge

Starting at 15th level your blood has permanently effected those around you. anyone you've had a long rest near also gains the benefits of 'walking library' until their next long rest, but they cannot add new information.

Networking

at 18th level, your blood connection has gained great power with those around you. the benefits of 'learn on the fly' are shared with those effected by 'spread the knowledge', however only one person my attempt 'learn on the fly' per attack, an benefits only extend to those within 60 feet of you.

 

additionally, if within 60 feet of a creature you can attempt 'field study' while it is alive, upon finishing it will become aware of your presence.