Blood Read

Using the blood of the targeted creature, you can ascertain three of the following traits: the target's true Race (if hidden by Illusory/Transmutative magic, or if the race simply isn't known), Vulnerabilities, Damage Resistances, Damage Immunities, Condition Immunities, Legendary Actions, Legendary Resistances, what the target's home Plane of Existence is or if the target is Undead. The blood can be collected in a phial and used to cast this spell ritually, or it can be collected from a weapon used to attack the target no more than 24 hours earlier.

If collecting blood from a weapon, the weapon has to have dealt an amount of damage to the target equal to or greater than a quarter of their max HP. It is at the DM's discretion whether or not they wish to divulge if the weapon has done enough damage. The caster does not have to have dealt the damage themselves, but simply be in possession of the weapon that dealt the damage. 

At Higher Levels: When you cast this spell using a spell slot of 6th level or higher, the caster can choose one more trait to learn for each slot level above 5th.