Improved Hunter's Mark

Your experience in hunting the various beasts of the world has given you a keen eye for anatomy and behavioural patterns.
You whisper or shout this information to your allies, helping them find weak spots to attack.
Whenever you apply Hunter's Mark on a creature, roll a nature check with the target's CON as DC.
On a succes, you and your allies gain a bonus of 2 to their attack roll and you learn one of the target's weaknesses, immunities, tactics or one of its Ability Scores.
You can choose what information you gain, and if this information is not available (for example target has no weaknesses) you may choose another until that information is available.