The slayer in the trio is the actual "false prophet" who sees the "real world" as magic-less and mutated. (e.g. Saladin’s Yusuf Ibn Ayyub).
The whicher (aka "the witch" / "the witcher") is a presumably fictional character whose job is to provide ideas and choices into their slayer’s mind. In my case it was Rindolf. In Saladin’s case, it may have been Aladdin.
The watcher is a true prophet, who monitors the slayer’s thoughts and guides them. He or she also often acts as a project manager. In Saladin’s case it was Maimonides / "Rambam" who was a famous amateur philosopher / creator / entertainer and also acted as Yusuf’s personal physician. Note that it took a long time for Yusuf to be aware of this fact.
In my case, my watcher from ~1989 until ~1997 was Melissa Joan Hart (MJH) who then transferred the lead role to the 1990-born Emma Watson. Confusingly, they both had acclaimed roles playing witches.
If you think that Emma Watson or MJH are not comparable to Maimonides, then see:
“If Botticelli were alive today he’d be working for Vogue.” — Peter Ustinov
“If Ayn Rand was born in the 1990s, she would be Christina Grimmie.”
Saladin was slain by Richard I "The Lion Heart" / Friar Tuck / Robin Hood. However, beforehand, Saladin de-hellholed Palestine except for parts of the coastal plain and his echoes begot some vampires, including Genghis Khan's direct-male-ancestor.