This series contains examples of:
- Blonde, Brunette, Redhead: Lydia and Elana have black and red hair, respectively, and when Rachel comes in later, she fills out the triangle.
- Different as Night and Day: Lydia and Elana are twins, but are opposites both in looks (Lydia is pale with dark hair, Elana is a tanned redhead) and personality (Lydia is snarky and aimless (at first), while Elana is seemingly perfect).
- Epistolary Novel: Lydia sends letters out to humanity in general, with introductions by Elana. Often, Lydia starts off by reacting to Elana's intro. The letters are mixed in with responses to questions from Real Life Tumblr users.
- Puberty Superpower: Averted; Elana is in her sophmore year of college when Lydia's powers start showing up.
- They Would Cut You Up: When Carter Pharmaceuticals expresses interest in studying Lydia, she's cool with it, but Elana is rabidly against it, citing this trope. Eventually, though, Lydia goes to see them without telling Elana - and it seems like there was nothing to be afraid of...