Collection Items - Upgrade Optimization

As a new feature, Collection Item (also known as Dolls) is still quite mysterious to a lot of people. Sparse maintenance kits and an endless array of things to upgrade; how to exactly use Dolls to your advantage in the most correct way? Well, in our book, there is no such thing as "100% correct", but we can give you some suggestions based on our computation.

Before we march forward, let's clarify several facts, starting from how many EXP each type of Maintenance Kit gives:

• Blue Maintenance Kit ×10 grants 200 EXP.
• Purple Maintenance Kit ×10 grants 500 EXP.
• Gold Maintenance Kit ×10 grants 1000 EXP.

We also want to know how much EXP is needed for each Doll level:

• R Doll (Blue) needs 1000 EXP per level.
• SR Doll (Purple) needs 3000 EXP per level.

However, this is not as important as knowing the Super Success rate for each type of Maintenance Kit for different levels of both Doll rarities:

With some maths, we can conclude that EXP serves as a pity, and we need to rely on Super% to advance your Doll to the next maintenance phase. For example, if you enter higher levels in a phase (due to bad luck), the chance of Super% increases. Phase is a group of 5 levels (0 ➔ 5, 5 ➔ 10, 10 ➔ 15). At the end of each phase, skills are upgraded, and the potency of that Doll jumps noticeably.

That aside, if you pay close attention, you will realize that certain Maintenance Kit rarities perform better than the others! That's what we are going to discuss today.

The first thing that comes to mind when studying this fact is to evaluate the efficiency of different Maintenance Kit rarities for different targets, based on their Super%. Let's say Purple has the highest efficiency for R Doll Level 1 ➔ 5, how much would my loss be if I used Blue or Gold instead? That's where the table from the previous section becomes handy, but this time, let's expand it further. We add a new column that calculates the efficiency of a specific rarity against the MAX efficiency available for that level.

The key takeaway here is that Blue Maintenance Kits have inherently worse Super% than the other two options. The efficiency of lower rarity kits also plunges as the phase increases with higher rarity dolls. If we transform the enormous table above into a short list, it would be:

• R DOLL:
• 1 ➔ 5: Purple > Gold > Blue
• 5 ➔ 10: Purple > Gold > Blue
• 10 ➔ 15: Gold > Purple > Blue
• SR DOLL:
• 1 ➔ 5: Gold > Purple > Blue
• 5 ➔ 10: Gold > Purple > Blue
• 10 ➔ 15: Gold > Purple > Blue

If we have a 4% chance of pulling an SSR, we can theorize that on average a player acquires 1 SSR every 25 pulls. This is the average luck, and we can implement a similar idea here. We have the "100% Probability Target", which is the average point where people hit Super% aka the mode. If you hit Super% before 100%, you are considered lucky, and vice versa. However, probability follows the Binomial Distribution graph, so your mileage may vary.

Now, if you try to add up the probability of the highest efficiency rarity over and over again (while keeping byproduct level upgrades in mind), you will notice that it exceeds 100% and even spills beyond >110%. This is no good, as you are traversing the "unlucky" hemisphere without knowing whether you are unlucky. So, the solution is to find a combination as close as to 100%. You would get something like this:

Here the ( ) denotes to the phase of the Doll, whereas [ ] denotes the summed probability. Keep the percentage as close as possible to 100%, but anything that costs less EXP and has a percentage of >100% might be more beneficial in the worst cases. Do keep in mind that these upgrades are performed in order from left to right because we utilize level ups to boost the chances!

• R (0 ➔ 5):
• 2× Purple [110%]
• 1× Purple + 3× Blue [107.8%]
• 6× Blue [108.8%]
• R (5 ➔ 10):
• 2× Purple [100%]
• 6× Blue [99.20%]
• R (10 ➔ 15):
• 1× Gold [Guaranteed]
• 2× Purple + 1× Blue [107.6%]
• 7× Blue [99.8%]
• SR (0 ➔ 5):
• 3× Gold + 1× Purple + 1× Blue [100.9%]
• SR (5 ➔ 10):
• 4× Gold + 1× Purple [102%]
• 4× Gold + 3× Blue [99.9%]
• SR (10 ➔ 15):
• 5× Gold + 1× Purple [99.9%]
• 5× Gold + 5× Blue [101%].

While this may not be the most accurate proposition, we can use this information to deduce how much EXP you need on average to level up Dolls from 1 ➔ 15. We also want to point out that EXP barely matters here. What's important is hitting that Super%. The reason we also emphasized the word "in order" is because we took advantage of the Super% increase with levels, so if your Doll is on the fence of leveling up, might as well level it up first with Blue/Purple/Gold before gambling again.

Additionally, we can also conclude that upgrading an R Doll to Level 15 first, then converting/replacing it with SR Doll (instant Level 5) is more resource-friendly, even if we include the combination feature. However, you lose the R Doll in the process, so it might not be a good idea if you are aiming for short-term CP padding or combat advantage.

This approach was proposed by the Discord User akusetsu (also a valuable contributor in Nikke Community Server) with the limited number of Maintenance Kits we have in mind. In the previous section, we mentioned that Purple & Gold Maintenance Kits trump Blue Kits, but while ideally we should avoid them, we cannot really avoid them as they are commonly found in Solo Raids and Dispatch. So, how do we handle this inevitable inefficiency? By balancing our spending so that none of the kits is surplus.

Let's begin with how many Maintenance Kits we actually get monthly:

• Total R kits: 453.78
• Total SR kits: 63.12
• Total SSR kits: 23.64
• Total R dolls: 10.5
• Total SR dolls: 3.87
• Total Treasure Items: 150

As you can see, we have way more Blue Maintenance Kits than Purple and Gold. If we just blindly follow the Resource Efficiency recommendations above, our stash of Purple and Gold would likely not be able to keep up! So, how do we handle this? We did mention before that lower rarity kits are way worse for higher phases, so prioritize Blue for lower phases first!

We will skip the minor detail and other calculation as they would be too long, but you can view the full version here in Nikke Community. In short, here's the outcome of this research:

Note that this recommendation would only make sense if you are aiming for Level 15 SR as it deals with balanced spending/inventory management more than efficiency. If you prefer to distribute your Dolls to multiple Nikkes evenly for CP padding and short-term Solo Raid advantage, it is much better to use the efficiency route or whatever you have in the meantime, but it is up to you to decide.

Collection Items - Intro

Collection Items - Dispatch

Collection Items - Priority