First of all, I know what you are referring to when you say NPC but what does the acronym stand for? Always wanted to know.
Anyway, characters do not have an IFUSED in their parameters list. So, you have to add it to the character's FPE. I usually make a copy the two files related to the entity and then rename them. I copy the BMP, and FPE files. No need to copy any of the texture files or the x file. I then edit the fpe file. For an example I wanted the fantasy character Dhor to activate another entity when (the player has just bought something from him and after the "contrived" transaction is completed then the entities show up in another area. So, he needed an addition to the fpe file. The following is what I had done. What is in bold is what I changed and added. Be sure and give the desc the same name as you give the files. Dhor 2 (ifused).bmp, Dhor 2 (ifused.fpe).
+++++++++++++++++++++++++++++++++++++++++++++
;header
desc = Dhor 2 (ifused)
;ai
aiinit = appear1.fpi
aimain = peoplepassive.fpi
aidestroy = user\destroy_and_activate.fpi
aishoot =
soundset = male
;spawn
spawnmax = 0
spawndelay = 0
spawnqty = 0
ifused = object1
++++++++++++++++++++++++++++++++++++++++++++
Now you will need to put in a special script in the destroy ai of the character in order to activate the door and for the wave file to play. I can't remember if I added this to the "destroy" script folder but I think it was an addition in one of the later versions but there is a script called "destroyandactivate.fpi". You will need to modify somewhat to play a wave sound.
;Artificial Intelligence Script
;Header
desc = Disappear then activate another
;Triggers
:state=0:plrsound=audiobanksound_file_name.wav,state=1,activateifused=1
:state=1:state=2,destroy
;End of Script
In this script the corpse will not remain as the character will be destroyed.
