Okay, I am here for you.
'Neather is scripted in: Entrance, 1N, 1N1W, 1N2W, 2W, 1S2W, 1S1W.
'Neather is hardcoded in: 2S2W, 2S1W, 2S, 1S, 1W.
Why? The rooms where he's scripted are relatively simple and possible to do with scripting without too much hassle.
2S2W, 2S1W and 2S have pretty complex interactions so they were either too hard or too much of a hassle to script.
1S is hardcoded... maybe because it's possible to stab 'Neather in the room and it was impossible to detect that with scripting? I don't remember if it was that room.
1W is hardcoded because of the dialogue options on stab.
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