ARAM in League of Legends is, by far, the best alternate mode in the game. It is incredibly fun to play and often acts as a stress buster from grinding ranked matchmaking all day.
ARAM’s full form is All Random All Mid. Going by the name, one can easily tell that unlike in League of Legends’ rated or unrated games, this mode will not allow players to select their own champions.
The selection process is quite random, but the system will not provide two players with the same picks on either side of Howling Abyss.
There has been a lot of confusion in the Valorant community about the entire champion selection process in ARAM. In a recent Ask Riot blog, the devs answered some of the more commonly asked questions.
When asked about the champion selection process in ARAM, League of Legends’ senior software designer Kurt “Mojibake” Glastetter replied:
“The logic for ARAM’s Champ Select is in a service we call TeamBuilder. The TeamBuilder server knows what champ every player has rolled, what’s on the bench, etc., for both teams. TeamBuilder prevents any player from rolling a champion that someone else has rolled.”
The League of Legends client’s Champion Select UI will only offer players champions that are on a re-roll, the ones that TeamBuilder tells it to.
TeamBuilder is what dictates team compositions. It takes into consideration many factors before suggesting a champion on a re-roll.
League of Legends ARAM Champion Select is completely random
Addressing the randomness of the League of Legends ARAM champion select, Mojibake said:
“As for whether it is “totally random,” that depends on what you mean. Every time you roll or reroll, the champion you get is randomly drawn from the set of available champions that you could roll at that moment, but that set is not random.”
Even the initial 10 rolls at the beginning of Champion Select takes into consideration all the available champions on one's bench before assigning a pick.
So, it’s quite possible that a single player can get a “streak of the same champ in different games, or a streak of champs you really like, or a streak of champs you really don’t like.”
Although the process is completely random, it doesn’t feel random at all thanks to TeamBuilder. It is this randomness that helps players discover new champions that they may not have thought of trying in any of their standard rated or unrated games.