General concept
Altars are the new type of mech which have proliferated across the galaxy since PARTIZAN, using the technology of the Kalmeria Particle. They replaced the previous Hallows and Hollows. Altars have access to strange and varied powers of their own, which can often change the pilot and cause physical sensations in those around.
Within Armour Astir, Altars are Tier III; previous mechs are Tier II whether or not they had been blessed by a Divine, leaving them at a combat disadvantage.[1] They engage with the world in one of five approaches.
Specific model
The generic name "Altar" derives from the first model using this technology, released by the March Institute about a year prior to PALISADE episode 1. While this mech has not yet appeared onscreen directly, it presumably uses the Arcane approach and is "focused on [...] little extensions off of a core frame".[1]