Loved this episode, and not just because I'm currently playing a tiefling alchemist in my buddy's Jade Regent campaign!
The Pathfinder alchemist especially works with both tieflings and dhampirs, with all the assorted body-horror type discoveries. The plan with Yarzu'ul (my tiefling alchemist) is that most of his discoveries go to enhancing his fiendish traits/abilities. Because hooves, talons instead of hands, a rat tail, and horns weren't enough!
Honestly the most fun with playing this character is the zany mix of mad genius with all the social grace of a drunk bull (Int 20, Cha 6). The character's introduction went something like:
*Tavern door is kicked open as tiefling strides in holding a bubbling vial* T!Alchemist: "SHUT UP EVERYONE, I'VE DONE SOMETHING BRILLIANT!"
Guard Captain: "I'm sorry-"
T!Alchemist: "Apology accepted. Now, try to keep up with my mind-numbing genius."
Amieko: "Yarzu'ul, what did I tell you about talking to people?"
T!Alchemist: sigh "The cards." Pulls a card out of his vest. "Hello stupid peasants."
T!Alchemist: "What? You told me to sacrifice verbal accuracy so as to facilitate comprehension by the unwashed masses, so I did."
Yarzu'ul: holds out a bubbly vial "Imbibe this" Horribly racist caricature of an old asian lady/party monk: "I no drink that! Do you want dead gramma?!"
When he drinks a con-boosting mutagen, Yarzu'ul's charisma drops to 4! Before he drinks if the first time, he told the party that it would remove his brain-to-mouth filter as a side effect. The general response was "There's a filter?"