It’s not easy to find online resources for this.

Here’s a page on the kinin forming system. The pathway we’re interested in involves Hageman Factor and Bradykinin.

Here’s a nice overview of the complement system and help understanding the c3 and c5 roleplayers.

Here’s a diagram of plasminogen to plasmin:
Plasminogen to plasmin

Revelation: this could be the biological correlate to xue yu leading to heat. Xue yu or clotting requires plasmin, and plasmin sets off the inflammatory cascade.

A picture of plasmin:
Human plasmin model