Regarding strength, Lucius was on par with a bona fide B-rated guardian and had the skill to hold out against an A-rated guardian for a short while. Even with this qualification, he was nothing compared to Demon threat-level beasts, and the Vermillion Mantle was the only means through which he could push his strength closer to the level.
This was the only power that would give him the strength he needed to defend against the war machines.
The beast gear was made from a powerful Demon threat-level beast with a unique trait. Unlike other beast gears where the user had to subdue the weapon before using it, the Vermillion Mantle was different.
It was usable by anyone, but not only did it require a staggering amount of energy to use, it also put its user into a state of unexplainable rage.