Editing Sonic the Hedgehog series (section)

===Master Emerald ===
[[File:Master Emerald Runners.png|thumb|244x244px|The Master Emerald, from ''[[Sonic Runners]]''.]]
[[File:SonicTailsKnucklesHPZ.PNG|thumb|right|[[Doctor Eggman|Dr. Robotnik]] steals the [[Master Emerald]] to power his [[Death Egg]], from ''[[Sonic 3 & Knuckles]]''.|181x181px]]
{{main|Master Emerald}}
The '''Master Emerald''' resides in a shrine on [[Angel Island]] and is guarded by [[Knuckles the Echidna]]; it contains an infinite amount of power, much greater than the seven Chaos Emeralds themselves, and is used to keep the Angel Island afloat in the sky. This giant, powerful green Emerald also has the power to fully control everything that the Chaos Emeralds do, including the ability to negate the energy of the Chaos Emeralds, as seen in ''[[Sonic Adventure]]'' and ''[[Sonic Adventure 2]]'', or [[Super Emerald|empower]] them, as seen in ''Sonic 3 & Knuckles''. The Master Emerald can also be used to power mechanical devices, and has been coveted by Dr. Robotnik since his discovery of it. The doctor once used the Master Emerald to power the [[Death Egg]] after stealing it from Knuckles in ''Sonic 3 & Knuckles''. During Knuckles' final boss fight in said title, [[Mecha Sonic Mark II]] powers up using the Master Emerald into a [[Super Mecha Sonic Mark II|short-lived Super State]]. In earlier media, the Master Emerald was sometimes called an "eighth Chaos Emerald", but this association has been lessened in later games, making it a separate but related entity. 

While it was featured prominently in earlier games, more recent entries have diminished the number of appearances of the Master Emerald.