Thanagar is the home world of the Thanagarian species.
In ancient times, Thanagar plagued by dark sorcery. Because of this, the Thanagarians crafted Nth metal weapons that can negate magic.
Since the formation of the Galactic Confederacy, Thanagar is a planetary member of the Confederacy.
Thanagar was was threatened to be conquered and forcefully annexed by the Shi'ar Empire led by Emperor Kral'Nor and from there expand into its system and galaxy. Fortunately, the Kryptonians try to mediate peace with the Shi'ar that led to the Shi'ar sparing Thanagar and refocused on conquering Krypton. The Krypton-Shi'ar War resulted with Kryptonian victory that the Thanagarians were very grateful for.
Thanagar also has a very tense interplanetary relationship with Gordania. Relations were eventually broken down with the threat of looming war between the planets. Councillor Winema Wazzo and the rest of the Confederacy tried to negotiate a settlement with the Gordanians; however, the Gordanians were willingly to attack Thanagar. As such, the Thanagarian government was doubtful that their situation with the Gordanians would resolve peacefully. When learning that Superman, the last Kryptonian, was on Earth, the Thanagarian High Command saw that the Kryptonian knowledge had survived with him and believed that allying with Superman would allow him to share his technology with the Thanagarians to counter the Gordanians. Lieutenant Colonel Shayera Hol was initially dispatched to Earth to offer Superman refuge until the High Command had changed their plans in having Hol to befriend him and curry his favor for the Thanagarians, despite her reluctance.