Heavy All Environment Suits started to enter service among
militaries of the world in the 2100s as interstellar colonization started to increase as a response to the need to put people in harms way in space for extended amounts of time. The first suits started out as up-armored space-suits designed to better withstand long term radiation in space but these designs would soon find use in combat, hostile environments, or anywhere that chemical, biological, or nuclear protections are required.
Over the next 200 years suit designs would continue to evolve. Heavy All Environment Suits would largely fall out of favor, instead being replaced by more specialized designs that are better suited for more specific roles.
The Birthday Class would be developed from existing designs by
ISOC's Green-Squad special forces unit as they transitioned from a range of piloting roles to infantry based operations as an increasing amount of drone usage necessitated a change in operational doctrine. As they were already very familiar with conducting operations remotely they did not require a lot of mobility and were quite used to operating from somewhat cramped conditions. Similarly their increasingly protective and engineering roles required heavy protection against a wide range of threats.
Their version of the suit was nick-named the Birthday Suit and the name ended up sticking.
Throughout the American Union, other sections of the military and civil defense units would end up adopting the Birthday class in various niche roles such as EOD as these units often didn't have the budget or inclination to develop their own HAES suit. By 2320, odds are if you needed a HAES suit in the American Union it would be the Birthday Class.
Do to lack of access to other suits, the Birthday class would become the standard heavy suit used within
the Magnetic Assembly for
Low-Cyborg operators. Green-Squad would continue to be the primary operators of the suit, largely using them for personal protection and combat engineering roles. This would see the suit used on
Azathoth,
Atlantica, and throughout Space Colonies in the
Hawking System. This familiarity would lead to further upgrade plans for the suit, extending its service life out for the foreseeable future.