As of the release of Chapter 2, Jim Culver is the default ally in for Level 0 Mystic decks.

First, Jim is the only Level 0 Mystic Ally since David Renfield) to provide a passive bonus to Will. That alone makes Jim playable. There are only a couple of situations where a pure Mystic would not want to run him:

• You plan on doing a lot of basic Investigate actions and want to know the top card of the Encounter deck (e.g. Alyssa Graham)
• If actively benefit from Token Manipulation (e.g., Katarina Sojka or Olive McBride)
• If you built around the Doom mechanic (e.g., Arcane Initiate or David Renfield)

Second, Jim Culver draws cards. A LOT of cards. At a minimum. Jim replaces himself the first time you take damage or horror. If you get him in play early enough, you can expect to 4-5 cards across the scenario.