Keeper


 * The Keeper is the guardian of Primus in the Marvel Generation 1 comic series.

The Keeper is a tremendously ancient Transformer, tasked with guarding the sleeping Primus for all eternity... then he died.

Marvel Comics
When the Autobot Pretenders were accidentally sent to Cybertrons core by Emirate Xaaron, they met The Keeper, and (more surprisingly) Primus Himself!

Though Grimlock was skeptical that he was facing the real Keeper of Primus, his doubt was put aside when the Keeper revealed Primus' origin (and by extention the history of the Transformers and Unicron).

Shortly thereafter Decepticons found the Autobots and launched an attack. The Keeper was killed early in the fight, and Primus was woken up shortly after.