Calantha or Kalanthia was an Off-world colony.
In 2007, the colony was sieged by forces assisted by the Tyrell Corporation. The organization provided a group of soldiers – namely Cal Moreaux and Avery – with a box containing two individuals who eliminated remaining hostile forces.
Iggy Cygnus was a combat model replicant who participated in battle in the fields of Kalanthia. Following a violent engagement, he came across the corpse of an enemy combatant. Iggy then proceeded to check the dead soldier's right eye and determined that the dead soldier was also a Nexus series replicant. He later recounted this experience in 2022 to fellow replicant Trixie, likening the two sides to "toy soldiers in a sandbox."
Calantha was mentioned in 2049 by LAPD Blade Runner K, as he questioned Sapper Morton inside his home. Upon noticing Sapper's utility bag, K mentioned that such bags were military-issue only, given to Nexus-8 combat models in warzones such as Calantha. K added that Calantha "Must have been brutal."
Behind the scenes
In Blade Runner 2049 (and its script), the colony is named Calantha, but in Blade Runner Black Out 2022, Blade Runner 2019, and Blade Runner Origins, it is named Kalanthia. Its name appears on-screen as Calantha in 2049 when K scrolls through Nexus-8 data files after retiring Sapper Morton. It is written as Kalanthia in 2022 when Gaff and another officer are watching the files of the replicants.