Don't Starve: Giant Edition

To unlock Willow you need to survive 8 days. You will unlock her on death or transporting through a portal once you've survived the required amount of days.

Willow's unique features are:

• She's immune to heat damage.
• She starts every level with a Lighter which acts as a torch with infinite durability.
• When her sanity is low she will start random fires at her feet.

The fact she has her lighter does make her a potentially viable choice for adventure mode, and if you want to try with an early character she doesn't take that long to unlock. Having to basically never worry about materials for torches etc is very nice.