Knowledge Devotion

You gain the following benefits.

Ability Score Increase: Increase your Intelligence by 1, to a maximum of 20.

Gain proficiency:  You gain proficiency in one of the following skills: Arcana , History, Nature or Religion If you are already proficient in the chosen skill,  you gain Expertise instead.

Knowledge Roll: When in combat, as a bonus action, you can do a knowledge roll of the corresponding knowledge skill, to see how much you really know about your encountered enemy

on rolls from: 

1 to 9, nothing happens 

10 to 15, Monster Lore: You learn the creature's damage resistances, damage immunities, damage vulnerabilities, and condition immunities.

16 to 20, You gain the previous benefit and have Advantage on your next attack roll against that creature.

21+ You gain all previous benefits, and for the remainder of the combat you add your Proficiency Bonus to one damage roll per turn against creatures of that type.

Arcana check for:  Construct, Dragon, Elemental, Aberrations

History check for: Humanoid types

Nature check for: Beast, Giant, Fey, Plant, Swarm of tiny beast, Monstrosities

Religión check for: Celestial, Fiend, Undead 

any other type of monster not in the corresponding skills, you do a normal intelligence check