It being only steam numbers is irrelevant. Assumption, you can't know this. (although it is probably true) You are interpreting the numbers incorrectly. Of course previous leagues will show a higher % of players quitting after the first month because those leagues had a much higher initial peak of players to begin with. No you're interpreting it incorrectly, the initial players do not matter, we are talking about retention not total player count. If you look at total players after the first month delve still has more players than other leagues after the first month. This would suggest that player retention is indeed better, in fact it makes it all that more impressive that it has higher player retention despite having less peak players than previous leagues. Furthermore, Look at December 2017 to January 2018. Its literally the exact same trend as Delve except its Abyss. Yes, this is most likely to do with the fact that it included an expansion, war for the atlas, which included a new end game boss on top of the league itself. I already said that abyss outperformed this league in terms of player retention. Comparing a standalone league to a league and an expansion isn't really that fair a comparison anyway imo.