Crystal Grimoire
It's not often Syndra gives away her spell books , however, it seems she is rather impressed with the skills you hold and has entrusted you with her Crystal Grimoire.
This item can be obtained by completing Key Character Prompts and allows you to earn an additional 4 bonus Crystals should you include Syndra alongside the Dextroluma that earned it in future submissions. Only one keepsake can be "used" per submission so they do not stack. When using a Keepsake DO NOT attach it to the prompt as the prompt will consume the item, simply ensure it is in your Character's inventory.