Now, unlike Juliet, Julian here is not a spoiler character for Gradients. It’s just that so far he has only appeared on the Friday Patreon’s strips. He’s the very first friend that Romeo made at College, before he even knew about the house where he’s living now.
He got the K because he is an avid sKater (I know, I know, a bit of a stretch), and he’s never seen without his skateboard unless he manages to get to a beach in which he trades it for a surfboard. His flower is the oddly named King Protea, which symbolizes variety and durability. Given how many bones he has broken in his life, yeah, that suits him. (There are other, a bit spoilery reasons for his flowers, but we’ll get to them when the story advances a bit).
Like Romeo, he is studying Modern English Literature. Unlike Romeo, he knows how to move around the city, so at times he acts like a guide for our hapless protagonist.