I recently challenged myself to build a bionicle MOC using system pieces, There are a few exception but for the most part I feel I sucededed
About this creation
Species: Great Being
Titles: Greed, The Greater, cannibal of souls, Essence of Greed and selfishness
Powers: Perfect soul, can exist outside of a body, immortality, Elemental Energy Distribution Alchemy (EEDA)
Personality Traits: Greedy, selfish, forever unsatisfied, Envious, Cunning, Egotistical, Arrogant, vain
Mask: In this form, his standard form, Kanohi vazulus, Mask of Restoration, which allows the user the ability to restore themslevs by borrowing the energy of another living being, or the ability to heal or reanimate someone using another living beings energy.
Keep in mind that I don't build system very often, if at all, so most of my designs won't be nearly as good as most of the other System mocs out there