I recently lost my Relic because I threw it into the Pyre of the Renunciation for Exciting Roleplay Reasons. Bad idea? Yes. I expected to become a less-useful cleric with no spells until such time as I found a new one.
But, oddly enough, I retain the ability to cast spells in line with my initial Broken Relic item that I was last attuned to, despite not having any relics in my inventory.
I am not clear if this is a feature or a bug. If it's the latter, I'll clear my spellcasting period and refrain from casting anything until I acquire a new relic.
GSID: LiAlH4
Character: Saibhon Dumein