"Titans can't be defined however, there's still too little we know about the successful application of these tags toady's given us since 47.xx ."
Could have sworn that was one of the tokens enabled for modder use amongst other ones that were previously exclusive to procgenned creatures.
I'm personally mostly wondering how custom experiments work, aside from using the [NIGHT_CREATURE] token for them - whether they require specific spheres to be made and/or the [SUPERNATURAL] token.
Squamous uses some interactions to transform the things they interact with afterwards, but in the tokens you could set up [EXPERIMENT_ONLY] interaction entries minus [GENERATED] and then connect the source_hfid to some example experiments.
If every custom necromancer in your world is barcoded to [SOURCE_HFID:1234] with [CREATURE:HF1234_NECROMANCER] and each experiment is respectively put in like [HF/EXP/1234 E_HUMG_/1] with [SOURCE_HFID:1234], it should in theory work with its constituent parts (which like color patterns reads the text directly for input). I do believe that this structuring might be so that worldgen knows when to disable experiments and the behaviour can pan out.
Its kind of a long shot but i've had interest in source_hfid for a while, and i work in the background trying to substantiate a effective use, since you can stamp certain potential trigger conditions like site guardians/unique demons in theory to civs, which i've tried/trying to do in order to generate specific leader circumstances so i can make more of a narrative, like making a Sauron big-bad so he can be gored by a random water buffalo or some circumstance as a premade character.