The Magi Sentinels (singular: Magus Sentinel) were an organization of robed individuals who protected the monarch of Onderon around the time of the Freedon Nadd Uprising in 3998 BBY. They were guarding King Ommin's subterranean fortress when Satal and Aleema Keto arrived for his aid in translating a Sith spellbook they had stolen.
By the time of the Clone Wars in 22 BBY, the Magi Sentinels were long gone, but the genetic abomination known as Zeta Magnus wore vestments that resembled theirs.
Some time later, the Imperial Sentinels developed by Darth Sidious to serve his Dark Side Adepts also donned cloaks and armors similar to the equipments of both the Magi Sentinels and Zeta Magnus.
Onderon's Magi Sentinels first appeared in Star Wars: Tales of the Jedi — The Freedon Nadd Uprising, a 1994 sub-series of the Tales of the Jedi series of comics, written by Tom Veitch. However, they were only identified as such by Abel G. Peña in the eNovella SkyeWalkers: A Clone Wars Story, which was written between 2008 and 2011 but only released in 2015. Peña saw the visual similarity between the unnamed guards in The Freedon Nadd Uprising and the Imperial Sentinels from Veitch's Star Wars: Dark Empire as intended, and thus made the connection more explicit while describing the similarly garbed Zeta Magnus.
Onderon's Magi Sentinels first appeared in Star Wars: Tales of the Jedi — The Freedon Nadd Uprising, a 1994 sub-series of the Tales of the Jedi series of comics, written by Tom Veitch. However, they were only identified as such by Abel G. Peña in the eNovella SkyeWalkers: A Clone Wars Story, which was written between 2008 and 2011 but only released in 2015. Peña saw the visual similarity between the unnamed guards in The Freedon Nadd Uprising and the Imperial Sentinels from Veitch's Star Wars: Dark Empire as intended, and thus made the connection more explicit while describing the similarly garbed Zeta Magnus.