From Fallen London Wiki
Choosing not to offer Yourself gives you a quality "St Gawain's Candle" rather than an item. You lose that, but you'd keep Your Very Own Severed Head if you had chosen the specific option.
Choosing not to offer Yourself gives you a quality "St Gawain's Candle" rather than an item. You lose that, but you'd keep Your Very Own Severed Head if you had chosen the specific option.