The Cohors Opera is the Republic's engineering and construction arm. It builds, maintains, and repairs the physical infrastructure upon which all other Branches depend. Without the Opera, the Republic has no territory; with it, every system the Republic touches becomes defensible ground.
The Branch is organised around Projects (Opera) executed by Workshops (Fabricae).
Unit structure
- Branch (Cohors Opera) — all engineers — Praefectus Operum.
- Workshop (Fabrica) — 8–20 engineers — Centurio — Architectus Primus.
- Crew (Grex Fabrorum) — 3–8 engineers — Decanus — Caput Fabricae.
- Engineer (Faber) — individual — Miles.
Specialisation roles
- Base Architect, Construction Operator, Ship Engineer, Infrastructure Tech, Orbital Engineer.
- Combat Engineer — attached to Legio under tactical command but Opera in rank and post-op review.
Project classes
- Class I — Minor repair. Decanus self-authorising.
- Class II — Standard build. Praefectus Operum approval.
- Class III — Major project. Praetor Operum approval + Consilium awareness.
The Praefectus Operum maintains a Project Register (Registrum Operum) listing all active construction and maintenance tasks. Emergency repair Crews may attach to ships or to ground operations under tactical authority of the requesting commander, with Praefectus informed within 24 hours.
Cross-Branch dependency: Arma (combat engineering), Subsidium (supply infrastructure), Medicina (medical facilities), Frontis (forward outposts). All requests routed through Praefectus Operum.
- Workshops are project-assigned, not permanent. When a major project ends, the Workshop is dissolved.
- Combat Engineers are Opera members, not Legio. Tactical authority during ground operations belongs to Legio; rank and post-op review remain with Opera.
- The Project Register is a doctrinal document reviewed by the Commissariat at each cycle.
- Opera is never idle. Opus et vigilantia.
Glossarium
- Fabrica
- Workshop — Opera's project-assigned unit.
- Architectus Primus
- Chief Engineer / Project Lead (Centurio rank).