A Boon is a type of Condition. It represents a mystic blessing that aids the investigator.
Blessed allows the player to count 4, 5, or 6 on a die roll as a success. This does not count for straight die rolls, such as removing an Injury during a Rest Action. If the player gains a Blessed Condition while they are already blessed, they instead flip the card and resolve the effect on the back. This effect can be a wide variety of things, but will always be of benefit to the player. If the player gains a Cursed Condition, they must instead discard the Blessing. On a , the player rolls a die and must discard their Blessing on a 1 or 2.
Righteous grants the player a small boost the player, allowing the player to gain an extra point of Sanity or a Focus during a Rest Action or Focus Action. During a , the player may optionally flip their Righteous to trigger the effect on the back, and discard the condition afterwards. This affect is generally very powerful, and usually gives the player the option of choosing from two benefits. This is the only way a player may lose the Righteous Condition.
Living Link grants a +1 boost to all skills. On a reckoning, the player flips the card and resolves the effect. It will always be of benefit to the character and will not cause the condition to be lost. If the player gains a Bane condition, they can choose to discard the Condition instead of gaining the Bane.
Composed allows the player to reroll all of their dice on a roll if they do not roll any 1's. They must flip the condition if they ever fail a roll. This could hurt the player, or give them a benefit at the cost of discarding the Condition.