Unlike usual souls, there are collectable special souls. There are two type of special souls. The passive souls have various effects on character the active souls give new skills to player. A player can get these special souls from general enemies and bosses. Sometimes, it is hidden secret places.
After clear each stage, player can upgrade his stats and skills with red souls. Higher level could increase skill's damage or add more attributes. Every skill has different master level. Mastered skill will show totally changed performance.