The Ruby Pure Heart is a massive, heart-shaped ruby that sits atop a mountain in the center of Pure Heart Valley. Previously, it projected a magical energy field that cloaked the valley from view to keep it safe from all threats.
In "I Love You Mao Mao", a couple of Adorabat's fellow Sweetypies remind her of the Ruby Pure Heart's protective effects, much to her annoyance. Orangusnake and his Sky Pirates seek to steal the Ruby Pure Heart for themselves, which Orangusnake believes will allow him to conquer the world. Unfortunately, while flying away after crippling the Sky Pirates' Airship, Mao Mao crashes his Aero-cycle into the Ruby Pure Heart. This creates a large crack in the gem, and its cloaking field drops, leaving Pure Heart Valley visible to the outside world.
With the Ruby Pure Heart damaged, Mao Mao and his friend Badgerclops--as well as Adorabat--are recruited to serve as the Sheriffs Department of Pure Heart Valley. Mao Mao is initially horrified at the prospect, until he learns of the Ruby Pure Heart and Pure Heart Valley's "legendary" status during a fight with Orangusnake. Mao Mao decides that defending the Sweetypies will allow him to realize his dream of becoming a legend. He thus prevents Orangusnake and his remaining pirates from stealing the gem, and accepts King Snugglemagne's appointment as the "Sheriff and Protector of Pure Heart Valley".
In "Orangusnake Begins", the Ruby Pure Heart absorbs a blast of energy from Orangusnake's giant laser tube, and begins glowing with an ominous purple light. When the frustrated villain later offers to sell his soul for the power to defeat Mao Mao, the Ruby Pure Heart releases the pent-up energy, which turns The Sky Pirates' Airship into Mechahossarafforangusnakerrang. During the pirates' subsequent attack on Sheriff Headquarters, Orangusnake reveals the source of his new power. After his defeat, Badgerclops briefly worries about this revelation, but he and his teammates are distracted; the Ruby Pure Heart is seen glowing purple again.
- Thus far, while the Ruby Pure Heart has appeared in the background of many episodes, it has rarely played an important role, with the exception of its power surge in "Orangusnake Begins".