Insights:

Complement precursors are made by the liver. They are then triggered by either Antibody-antigen complexes or microbial sugars and antigens.

Complement factors are proteolysed to an A and a B component. Complement factors can combine to form enzymes that catalyse the next step in the cascade. The main steps are proteolysing C3 and C5.

The A components of the common pathway (C3 and C5) are pro-inflammatory in that they increase vascular permeability and attract neutrophils.

The B components are more structural, e.g. C3b is an opsonin and C5b goes to form the membrane-attack-complex that's important in combating Neiserria infections.

Image credits:

http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit5/innate/activation%20of%20alternative%20pathway%20C5.html

http://faculty.ccbcmd.edu/courses/bio141/lecguide/unit5/innate/c3case_flash.html

https://www.immunology.org/public-information/bitesized-immunology/systems-and-processes/complement-system