Apologies for the long response, I have a lot of ideas on this topic. 
Also, my thoughts are more general and not specific to anime games past the first paragraph.
It’s an interesting concept I think, but you’ll run into copyright issues fast. If you don’t own the rights to use it, don’t use it. That means you have to make up your own anime universes; you can’t copy or use the likeness of any existing anime without explicit permission.
If you don’t keep that in mind, your game will most likely get taken down by someone. Legal stuff is a mess.
Dev Product Time Rifts: Monetization in video games really relies on your morals, if any. For me, I dislike pay-to-win or pay to have an advantage things. Time savers or outright buying collectibles is not a good idea in my mind. I say that as it seems the dev product for the time rift would be skipping gameplay. It’s fine if you want to add that into that game, but realize what that means: skipping gameplay in some way.
Gamepass swords: I’d make them cosmetic only; that means no gameplay changes with the swords. But, that’s not going to make some people happy. Some would love to spend money for that better weapon, but it truly up to your morals. You are the game developer after all.
Subscription service system: I think subscriptions are predatory by nature as you don’t fully own what you pay for, but I digress. Maybe add a battle pass, but that might be too much work. You could use the subscription system like a Kickstarter or just a donation system. Be VERY clear about what the user gets with the subscription though.
If it’s just giving you money, and they get nothing in return other than satisfaction, say that.
Donation Dev Products: As mentioned above, this could be done through the subscription service. It could also just be dev products.
Premium Payouts: Roblox gives developers robux for players playing in their game if that player has Roblox Premium. So, give premium players a reason to play your game with, maybe, exclusive gameplay. The main thing here is cosmetics, but that only goes so far.
Merch: This is usually outside the scope of most games, but could be a good option. If I had merch for my game, I’d make it minimal. Most don’t want a shirt or something that screams your logo or something.