The use of Relics is a core gameplay mechanic in Knack that is used primarily to alter his physiology and appearance, augmenting his abilities and making Knack a formidable force to be reckoned with. Relics are found by destroying items or killing Goblins, and are picked up by walking near them.
Health
Knack can use Relics to restore his health, allowing him to maintain his presence on the battlefield for longer stretches of time.
Sunstones
Sunstones are a type of Relic that fill up a separate meter near the health bar, and enables the use of some of Knack's Special Moves. These moves are incredibly devastating, often turning the tide of an encounter, and are capable of clearing an entire battlefield of a threat.