I spoke with a recruiter over the phone, who asked me general questions about myself and why I chose to apply to Riot. It was definitely the most casual interview I have ever had, it felt more like chatting with someone at a party (we even talked about the current meta, our favorite champions, LCS, and so on). He gave me what was essentially the full rundown of what Riot is about, what they look for in potential Rioters, the interview process, and so on. He even provided me with the Riot Not for Tourists Guide to L.A., which I thought was an awesome way to get more information about the city outside of typical Google searching.
A couple weeks later, I spoke with the hiring manager for the Editorial Writer team. He asked more in depth questions regarding what I would want to do as a writer for League of Legends.
A few days later, we completed a writing test on Skype: this involved the manager sending me a link to a page about their champion figures, and asking me to rewrite it in my own words in 15 minutes (pretending that I had unlimited resources and time to work with). He asked what I felt were the strong and weak points, then had me take 10 minutes to revise it and send it to him. We repeated this process one more time before he asked me who my favorite champion was and my favorite skin for that champion. He then sent me to the NA skin spotlights page, asked me to read over a few of them, then create my own spotlight for my favorite champion's skin (again in 15 minutes). He again asked what I felt were my strong/weak points, and had me revise it in 10 minutes.