The items you find and use, upgrade items, Skill Points, Spirit Emblems, and sen can all be viewed and managed through your Equipment and Inventory menus.
At the bottom of either menu, you can see your Vitality bar and Resurrective Power charges, Unseen Aid percentage, Vitality and Attack Power levels, Skill Points earned and experience needed to earn the next Skill Point, Spirit Emblems, and sen.
The Equipment menu allows you to review and apply Prosthetic Tools as well as set the items you wish to equip in your Quick Items slots. You can apply up to three Prosthetic Tools and up to five Quick Items.
Visit the Inventory menu to see all the items you've collected in your quest, including Quick Items and Prosthetic Tools.