The time has come to finish what we started one thousand years ago. Now, go forth, and destroy every plant, every animal -- everything that lives and breathes. Then, together, we will build a glorious world of metal. Rise my warriors!
— Lyric the Last Ancient, Sonic Boom: Rise of Lyric
The Sentinel is a machine that appears in Sonic Boom: Rise of Lyric. They are a mass-produced line of titanic robot warriors created by Lyric the Last Ancient. The Sentinels were Lyric's ultimate weapons in his endgame against all organic life on earth, being the very force meant to wipe it out. During his two attempts to dispatch them however, they were stopped by Sonic the Hedgehog and his allies.
The Sentinels are colossal robots of epic proportions, each being as a tall as a skyscraper, if not more. They are humanoid in shape, being composed of reddish-brown metal, and have red eyes. They possess a round torso with a round intake chamber in the middle that glows yellow and three-fingered arms which are longer than their legs. Their heads have no visible neck. They also have helmet-like features and a pair of horns that outline a circle, although the one on the right is longer than the other.
Sonic Boom: Rise of Lyric
The Sentinels were created a millennium ago by Lyric the Last Ancient. Having developed a blind hatred for organics, the Sentinels were meant to realize Lyric's ambition of creating a world of metal and robotics by destroying all organic live on earth and then rebuilt the world as he desired. From within Lyric's Weapon Facility, the Sentinels were mass-produced, with an entire army of them being assembled at his lair. The only thing they needed were the Chaos Crystals to power them. Before Lyric could get them however, Sonic the Hedgehog and Tails, who came from the future, helped a rogue MAIA unit take control of a partially built Sentinel which she used to stop Lyric and help imprison him. With Lyric gone, the Sentinels were shut down. while remnants of them would end up in Cliff's Excavation Site.
A thousand years later, Lyric escaped and resumed his plans to reboot his Sentinel army with the Chaos Crystals. After Lyric brought the Crystals to his lair, he finally brought Sentinel army online. Before they could be unleashed on the world however, Lyric was defeated by Team Sonic. The Sentinels were then shut down permanently after Sonic got rid of the device Lyric used to control them.
Powers and abilities
Little is known about the Sentinels' capabilities. However, their enormous size gives them immeasurable physical strength. While their true potential is unknown, they are implied to be an unstoppable force of mass destruction. Even Sonic had his doubts about facing just one Sentinel in battle. A lone and incomplete Sentinel was powerful enough to lay waste to Lyric's Weapon Facility and stop Lyric's iron-clad plans in their tracks, and an entire army of them can destroy all life on the planet.