Why do I feel like this suggestion was made before. Do post a link if so.

Fame can go negative, when it does, it is counted as being infamous while having positive fame is counted as famous.

You gain negative fame when you attack someone with positive fame and win.
Conversely, whenever you attack someone with negative fame and win, you receive positive fame.

Negative fame gain follows the basic formula of fame gain. (Attacking high fame players gives u negative fame more. The player you attack also lose fame.)
Other ways of fame gain still works.
You can't get negative fame from losing fame of getting attacked.

While I think there should be other ways to gain and lose fame from voodoo like black death or TIs. I am not sure about what formular for their value.

Bonuses for certain infamous levels or famous levels.

Famous
Every 1 mill positive fame : 0.5% Cheaper ship upgrade. (Degrade by 1/2 each step. 0.5, 0.25, 0.125, ...)
Every 5 mill positive fame : 0.05% Cheaper GB. (Degrade by 1/2 each step.)
Every 10 mill positive fame : 1% extra max health of ships. (Degrade by 1/2 each step.)
Every 25 mill positive fame : 5% extra damage resist from Iron Scantling. (Degrade by 1/2 each step.)

Infamous
Every 1 mill negative fame : 0.5% Cheaper ship upgrade. (Degrade by 1/2 each step. 0.5, 0.25, 0.125, ...)
Every 5 mill negative fame : 0.05% Cheaper GB. (Degrade by 1/2 each step.)
Every 10 mill negative fame : 1% extra ship damage. (Degrade by 1/2 each step.)
Every 25 mill negative fame : 5% extra avoid from Copper Plating. (Degrade by 1/2 each step.)

If i am right in assuming fame that fame is based off of a percentage of the defenders fame in plunders it would be impossible to go negative

Tom Hargreaves wrote:If i am right in assuming fame that fame is based off of a percentage of the defenders fame in plunders it would be impossible to go negative

The suggestion is that if your fame is near 0 and you attack someone with positive fame, you would lose fame and start to go negative, same with when you attack someone with negative fame, you gain fame.

1000000 - 100000 = 900000
100000 - 1000000 = - 900000
900000 + 100000 = 1000000
-1000000 + 900000 = - 100000