Tristan is expensive, but Preston doesn’t mind expensive. For some, he can function simply as a Darkhorse that provides soak. (And they stack.) But the rogue card people associate most with two stats is lockpicks, which Finn and Trish would appreciate a perma +2 with. Playing him for free will require a table wide commitment to fill in the bag, or not trap all the tokens for other uses. At worst, it’s a little upside when someone pulls three blessed tokens in a row. If someone has two Favors in play, the trigger becomes “when a test involves a blessed or cursed symbol“ which is inevitable.
트리스탄 보틀리
Fixer for Hire
조력자. 범죄자. 저주받은.
After your turn begins: Choose two skills. Until the start of your next turn, you get +1 to each of those skills.
After any skill test ends in which a total of 3 or more or tokens were revealed: Play Tristan Botley from your hand, at no cost.

Some rough math on Tristan's reaction ability, ignoring bag-manipulation/Favor/Covenant/etc effects:
With 10 total bless/curse remaining in bag during the current test, there's about a 5% chance of triggering him.
With 15 total, there's about a 10% chance.
With all 20 in the bag, there's about a 15% chance.
(For a base 16-17 token bag.)
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(Personally, I've only ever seen him get played full-price, but even then the effect is quite strong and flexible, and is an especially reasonable choice for small-collection investigators looking for a generically-useful ally.)
In case you haven't noticed, this guy does not have an ally slot symbol printed on him. Which makes him really great in my opinion. Yeah he is expensive, but you can pair him with other allies without needing charisma