Harvesting

From Heliana's Guide to Monster Hunting

The Harvesting check is the summed total of two ability checks: Assessment and Carving. A single creature can choose to make both checks; if it does so, it makes these checks with disadvantage. With all Harvesting checks, the skill used for the check depends on the type of creature the characters are attempting to harvest. For example, beasts require a Survival check while aberrations require an Arcana check.
Assessment. To correctly assess how best to extract and store creature components, a character must make an Intelligence check. The skill applicable to the check depends on the type of creature, as shown in the Creature Types and Associated Skills table. A creature attempting this Assessment check is known as the assessing harvester.
Carving. Skill with a knife is the proven method of harvesting components. A creature attempting to harvest a corpse makes a Dexterity check. The skill applicable to the check depends on the type of creature, as shown in the Creature Types and Associated Skills table. A creature attempting this Carving check is known as the carving harvester.
Ritual Carving. For some creature types, magical rituals can be performed instead of getting elbow-deep in grisly viscera. When making a Carving check to harvest an aberration, celestial, elemental, fey, or fiend, a carving harvester with a spellcasting ability can make the Carving check using that ability instead of Dexterity.
Spells and Buffs. For a spell or magical effect to have any influence on the outcome of harvesting, it must affect a harvester for the entire duration of the Harvesting check (see Creature Size and Harvest Time table below). For this reason, spells with a duration of 1 minute, like bless and guidance, never confer their bonus to the result of the check. A spell like enhance ability, which lasts 1 hour, could confer its advantage to a Harvesting check so long as the spell begins before the check starts and does not end until after the check is completed.

Assessment check = 1d20 + Intelligence modifier + proficiency bonus (if applicable)

Carving check = 1d20 + Dexterity modifier* + proficiency bonus (if applicable)

^{*or Spellcasting ability modifier if it can be ritually carved.}

Harvesting check = Assessment check result + Carving check result

Harvest Time and Helpers by Creature Size

Creature Size	Helpers	Harvest Time
Tiny	0	5 minutes
Small	1	10 minutes
Medium	2	15 minutes
Large	4	30 minutes
Huge	6	2 hours
Gargantuan	10	12 hours

Creature Types and Associated Skills

Creature Type	Harvest Skill
Aberration	Arcana
Beast	Survival
Celestial	Religion
Construct	Investigation
Dragon	Survival
Elemental	Arcana
Fey	Arcana
Fiend	Religion
Giant	Medicine
Humanoid	Medicine
Monstrosity	Survival
Ooze	Nature
Plant	Nature
Undead	Medicine