Strengthening Synthesis (強化合成), commonly shortened to just "synthesis", is the process of giving materials (素材) to a flower knight in order to power them up. The flower knight being powered up is called the "base". Materials can include Manyus, Ampules, Skill Flowers, Equipment Flowers, and even other flower knights. The effects of strengthening synthesis include leveling up your flower knight, increasing their skill levels, and unlocking their equipment slots. You can feed up to 10 materials to a flower knight at once. It costs gold to do a strengthening synthesis. Strengthening Synthesis can be done by going to the Character Management page by clicking on the Character (キャラ) button and clicking on the third tab labeled Strengthening Synthesis (強化合成).