The thing about Heiji is—he inspires a strong sense of solidarity in Stiles that he hasn't really known...well, ever. Scott may be his best friend, but they aren't particularly alike. Which is fine! More than fine. Opposites attract and all that. It's just that Stiles trusts Heiji a hell of a lot sooner than he trusts most new acquaintances.

"I'm thinking the same thing. Things are pretty chaotic here. Maybe your family sensed that. Being all..."

Here, he makes a wiggly-fingered gesture at Heiji, as if to try an encompass his magicky-faeness.