The way sanity created the system is actually very simple, the first id you put is the npc id like so
Code:
//Abyssal demon
1615
After that you put the rarity of the drop, basically 0-rare number
Code:
//Abyssal demon
1615:30
After that you start adding items and item amounts to the normal drops which is on the same line as the npc and the rare number, like so
.
Code:
//Abyssal demon
1615:30 995:1000
Basically so far,
1615 - Npc Id
:30 - Rare number
995 - normal drop id
:1000 - drop amount
Then on the line under your normal drops you put in the rare drops, like so
Code:
//Abyssal demon
1615:30 995:1000
4151:1
Outcome:
If you kill an Abyssal demon it will pick a random number between 0 and 30, if the number isn't 0 then drop a normal drop, in this case 1k, if the random number is 0 then drop the rare drop, or whip.
Adding more then 1 items to the lines will make it so it picks a random drop out of the line.