Weakening system (antibodies) like in the Forgotten Realm

The system is approximately the same as in the forgotten kingdom.

Antibodies are needed to increase the degree of attenuation.
If your antibodies are less than 50% of the virus concentration, then you will have a weakening level of 9. You will quickly lose health on the floor.

9 50%
8 55%
7 60%
6 65%
5 70%
4 75%
3 80%
2 85%
1 90%

I view attenuation levels as

6 - light
7 - normal
8 - hard
9 - impossible

Energy most likely increases your bm (attack?), although this is not written anywhere. But by analogy with the forgotten, this is so.