With all the issues for nutaku Aigis, it's pretty obvious why it doesn't attract a ton of new players. If I was recommending Aigis to a friend, there's no way I'd point them to our version. It's also not the flashiest game out there, so unless you know before hand that it's actually the gameplay that sustain the game, you'd probably try one of the others first.

Dragon Providence on the other hand, has a couple of things going for it: 1) It's at the top of the game list (people usually start there), 2) it has a mobile version (a much wider market). Despite that, I'm willing to bet that DP probably has the worst player retention of all the games on Nutaku. Most players quit within days, if not weeks. Guilds are constantly having to rebuild/merge due to their players consistently bleeding away (not to mention the countless dead guilds). It is probably the biggest whale trap I've ever seen, with every event and (decent) new units/card asking players to shell out hundreds of $.

The other rankings seems fairly reasonable, with newer games tending to get more new players trying them out. The only somewhat surprising bit is that Hitsuji got the kind of population to be 5th overall despite all its launch issues, but that might say more about the other games than itself.