The interview took place over four rounds: two over Skype, one on-site, and one final Skype call with a member of the leadership. The questions asked were a mix of technical, fit, and competency. I was asked to elaborate on my background as it related to the position, talk about what I can add to the company during the internship, and what I hoped to take away from it.
Overall, the communication throughout the process was very smooth and professional. Everyone that I talked to were very friendly, with the exception of the interviewers during some of the "high pressure" interviews, but that's to be expected. It took a total of two months; the Skype interviews were 45 minutes each, and the onsite took an entire day.
If you want to succeed in this process, you need to understand that cultural fit is very important to the company. Riot values teamwork, communication, and a passion for LoL that translates into motivation to make the game better. You need to display this passion in your application and your interviews.