You can sell your created abilities, including custom jutsu, custom summoning contracts, custom elements, everything. That can be your income if you like creating. Custom elements usually go for 5k, individual customs can be sold in scalable amounts up to 5k so if you get max profit by connecting with the right people who desperately want what you have for 5k a pop you can get your Children of Tiamat biography by selling five custom slots. Keep in mind you get 6 slots per custom jutsu, so that means 1 of your customs, sold to the right individuals can make you 5000 kumi x 6 slots = 30000 kumi. That's investing in the creation of one custom you can sell, make that bitch worth it and you'll get what you've earned. The system to gain exponential kumi wealth is there.
You can also sell biography templates, someone just sold me one for 4k and they can sell for up to 5k as the system allows single things to be sold for at maximum 5k. That's 5 biographies at max profit and you have a Children of Tiamat biography or Yin/Yang and those are high tier 5 abilities. You're getting EIG in 2, or Poison Ninjutsu in 1. This is another way a non-NW-roleplayer can gain a steady source of income. If they like making biographies look dope for other people and are good at it they can do that and get paid to.
Also, prizes for tournaments are still rather big things let's take the last tournament and
@ReXii for example he just got a
Sage Weapon for his prize along with other things including a special artifact, and a new biography specialty. That's worth more than 25k kumi in retrospect. If he had taken just plain Sage Rank, which was an option, sans Sage Weapon that is a 25k kumi prize. That's not including the secondary Time Dial and the tertiary biography specialty. That's easily a 35k kumi prize for the tournament. You like fighting in tournaments and you're good at it? Do it, it's worth the investment if you can win, you're getting a value worth a tier 5 ability.
The system doesn't revolve directly around the NW itself, the NW is just a way to access currency for being active in it and differs from trading because like battling it is a "production" method over a "circulation" method. You can instead battle to gain it, trade to gain it, sell things to gain it, but you have to do something. You're not going to get it by doing nothing at all, you have to interconnect with and roleplay with others, find people willing to buy your things, create things worth buying etc. Merchants can even sell their creations for ryo or kumi respectively, which can be a source of income.
There are various ways to obtain it, and it has an economy built around it. The main difference is missions in the NW, and battles in the battle arena produce it. Trading customs etc doesn't "produce it" it merely "circulates" already created kumi. Then of course spending it on abilities destroys it. That is an economy by definition and makes it so everyone can have access to what they want. Compared to the archaic permission-based system which judged people solely on how well others thought they were. Now individuals have the ability to directly take the initiative to get what they want.
Look at me, I went from nothing to having full Yin-Yang in a year. Something I would have never gotten without the system.
As a returning roleplayer, I just don't think you get all of the ways you can obtain kumi which is understandable.
You have some dope oldie cj, or are really good at creating customs people vie for? Sell em.
You have biography making skills, that attract people's eye? Use em.
You have battle skills and want to beat the shit out of people for kumi? Do it.
You want to play solo and do missions, building a story of your own, while being compensated? Go for it.
You want to win tournaments and get tier 5 abilities? Again, do you.
You can sell anything you have, but the shirt off your back, and knowing this roleplay you might find someone willing enough.
People even doing shady black market deals, selling their accounts and stuff. Just don't get caught, and if you get burned it's on you.
I didn't tell you about that last one, if any one asks. It's just between you and me, and this happy little tree.
Edit: Rereading what you said fully if you're asking "Can roleplayers come back after 4 months and have accumulated wealth for no reason." Nolol. Activity = rewards. Inactivity = nothing. Just find the activity that works for you, and lean into it. No one is going to get paid for just sitting around, you'd not be doing anything worth abilities if you're not playing. So for example, if you want to show up once every month for a battle, then if you win you'll be getting 500 kumi, though you shouldn't be rewarded as much as someone who is avidly battling numerous people, or someone who is working tirelessly in the NW, or creating cj non-stop, or busting their ass on biographies etc.
It's also my personal opinion there shouldn't be any payment for inactivity, ever, nor do we need a passive income system. Even mods and sensei only get paid for working, not for just existing. Power creep happens when people play the game. As someone with full Yin-Yang, Medical Ninjutsu, and every other ability, you shouldn't feel power creep unless you're talking about missing out on the meta. Yeah, you're behind on the meta because it shifts. Customs changed. Boosts and abilities are paramount right now.
