User blog:Babyghost853/Fusion Explained.

Mr. Mistoffoles Zombie Fusion Guide (updated 4-25-2012 rev5)
This guide is for people who are a bit confused on the fusion of zombies. It is not meant to be official as I do not work for Gree. It is mostly built on my own documentation of fusing several thousand zombies, but I welcome documented contributions. It will be updated as necessary.

Latest updates - Answer to question of how cards level up by MotorSlave added. Updated the bonus/penalty for fusing cards of different colors. Also updated the math behind using leveled up rares as feeder cads for your best cards.

What is Fusion?

Zombie Fusion is where you sacrifice (lose forever) several weaker zombies to make one zombie more powerful. The zombie you are trying to improve is the BASE CARD. Every zombie you sacrifice adds GROWTH to your BASE CARD. This growth is a percentage - reflecting how close you are to getting a level. So a growth of 40% (for example) means that the card gained 40% towards it's next level. After Fusion, if your BASE Card did not gain a level, you are told how close you are to your next level.

It is possible to sacrifice multiple cards at a time however I do not suggest you do this for reasons that I will explain later on.

No, You tell me NOW!

Fine. There are three reasons. Bugs, Math, and Tokens. What Cards do I sacrifice?
 * Bugs - There is a bug that will sometimes prevent you from getting your attack and defense bonuses for gaining a level, if you gain multiple levels in a single fusion, as can happen with multiple sacrifices. I have heard of a bug that causes you to actually lose attack and defense. I have never, in thousands of fusions, experienced this with a single sacrifice at a time.
 * Math - Every card is supposed to have a specific ATTACK and DEFENSE value it climbs to for each level (all level 5 Rocker cards are supposed to be identical for example). However, that is a CALCULATION, and when you do multiple card sacrifices, it can throw that calculation off. You get cards that are a point or two more powerful, or weaker, than their counterparts. That annoys me personally. If it doesn't annoy you, then don't worry about this bit (worry about the bugs and the tokens isuses instead).
 * Tokens - It costs a certain number of tokens to sacrifice a card: (Base level + sacrifice level) * 100 for the curious. If you sacrifice multiple cards and gain a level as a result, the game charges you 100 extra tokens. It's a mild annoyance. But when you are growing a lot of cards, it adds up. Early on in the game it is a BIG DEAL. Later on, not so much. This 100 tokens is because the game calculates each card's sacrifice individually and when it sees you have gone up a level, it charges you for that next level.

You want to sacrifice your weakest cards. Early on that will be Normal cards (N). All N cards will grant a given base card the same amount of growth. It doesn't matter what the card's attack or defense or force or cost or picture is. The amount of growth is based on rarity. Likewise, all N+ cards will grant the same amount of growth (more than an N card). All Rares, the same. All Rare+ cards, the same. I assume all S Cards too - but who would be nuts enough to sacrifice a super rare?

What Cards do I Grow?

The obvious answer is "your best cards". However, there is a less obvious answer - sometimes it is worthwhile to grow cards you intend to sacrifice. Each level above 1 the sacrificed card has, adds to the growth of the BASE card. So, for very high level cards that don't grow much, adding levels to your sacrifices is a cheap way to add growth to the BASE card.

Why not just sacrifice MORE cards in that case?

Oh. you will have to... but consider this - a Level 19 card costs 2000 tokens for EACH sacrifice. And most cards only grant 5% growth. So sacrificing six cards grants 30% growth and costs you 12,000 tokens. If you grow a card by 6 levels, it also gives 30% more growth (well, not really - depends a bit, more on this later). That card will cost 600 more tokens to sacrifice, but will give the same growth as SIX cards - so, for 5100 tokens (2000 tokens for the card, 600 for the levels, 2500 to grow it to level 6 first), you get 12,000 tokens worth of growth.

You had Better Explain That Better

Sure. First you need to know about BASE GROWTH RATE. The BASE GROWTH RATE of a card is what the card will grow, if it is level 1, and you sacrifice a level 1 N Card to it. Next, you need to know about the GROWTH CHART. Here it is.
 * R Cards - Base Growth Rate is 89%
 * R+ Cards - Base Growth Rate is 80%
 * S Cards - Base Growth Rate is 70%

<-- 5%, 5%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 89%, 94%, 99% .... --->

This is a sliding chart, and it is best to explain it by giving examples. Take a level 1 base card, and sacrifice a single level 1 N card to it. You will not gain a level, but you will gain 89% growth. If your Base card had been level 2, it would slide down one rank to 85%. If the Base card had been level 1, but the sacrificed card was level 2, it would slide up a rank to 95%. So you see, by looking at a limited number of variables, you can tell how much growth to expect from a given fusion. The Formula is: Growth rank change from BASE GROWTH RATE = SACRIFICE LEVEL - BASE level + RARITY BONUS + COLOR PENALTY
 * The Base Growth Rate goes DOWN ONE RANK (for example, from 40% to 35%) for each level the BASE CARD goes up.
 * The Base Growth Rate goes UP ONE RANK (for example from 20% to 25%) for each level the sacrificed card goes up.
 * If you sacrifice an N+ Card instead of an N Card, you get a 2 rank bonus (verified)
 * If you sacrifice an R Card instead of an N Card, you get a 4 rank bonus (verified)
 * If you sacrifice an R+ Card instead of an N Card, you get a 6 rank bonus (verified)
 * If you sacrifice an S Card instead of an N Card, you should get an 8 rank bonus, but that would be foolish to do. (thus not verified)
 * If the BASE CARD and fused card are not the same color, the growth goes down two ranks (Red base, blue card for example)

Example:

Base card is Red Level 3 with base growth of 70% (a super-rare card!). I Sacrifice a Blue Rare, level 10.

Growth = sacrifice level - base level + rarity + color penalty so... Sacrifice level 10 - base level 3 + 8 (R card) - 2 (blue card sacrifice, red base card) = 13 If you look at the chart, you see it goes up in 5% increments. The base is 70% for this card. 13 * 5% is 65%. 70% plus 65% is 135%. The base card will grow by 135% (actually by 134%, but it's simpler just to assume 5% jumps).

I sometimes see growth that is not in increments of 5%, what is up with that?

The 89% growth rate and the rates after it are not a flaw - it's just how the chart is. But sometimes you will see a card grow by 34%, or 29% for example. This is a mathematics thing. The chart is not purely in 5% increments, but is best thought of in that way. Sometimes due to rounding it comes out as 4% or 6%. This happens most often when you sacrifice multiple cards or when a sacrifice causes a card to gain a level (and the game has to recalculate the growth based on the new level).

Why does the chart have a lot of 5% values on the left side?

Because 5% is the minimum amount of growth you will get for sacrificing a card. But, as the Base Card goes up in levels, it still gets worse. You can be multiple levels into the 5% minimum. What this means is that as a BASE card goes up, it is possible for even higher level sacrifices or higher rarity sacrifices to give less growth (down to the 5% minimum). It means that eventually no matter WHAT you do to a normal card, it will only give you a 5% growth rate.

Example: A red card with a base growth of 60% is at level 15. This means that the growth for a level 1 N Red Card is:

1 - 15 +0 +0 (level 1 sacrifice minus level 15 card plus 0 for rarity plus 0 for color) = -14

If you go down 14 ranks in the chart, you will see you are (still) at 5%... but actually 2 ranks deep into 5%. --- 5% (you are here...), 5%, 5%, 10%, 15%...

This means that before you will get above 5%, you actually have to rise THREE Ranks - a level 2 or 3 N card will only give 5%, and it takes a level 4 N card just to get to 10%.

When you start to raise cards that are level 20, 25, 30... you need high level rares to get beyond 5% growth.

So What Do I concern Myself With for Fusion?

BASE Card COLOR and LEVEL

SACRIFICE Card COLOR, LEVEL, and RARITY

Nothing else matters - not the rarity of the base card, the picture or name of the card, the cost of the card, Force of either card, Attack or Defense of either card, etcetera.

Can you Explain The Math Behind Why You Save Tokens Sacrificing Higher Rarity or Level Cards?

Yeah. Updated and Clarified, no less.

First, realize that I generally sacrifice Red N Cards. This is the most common, easiest type of card to get. And boy do I get a lot of them. The mathematics here works regardless of the color BASE Card though, because I sacrifice (usually Red) N Cards until the growth for the base card hits 5%. That happens earlier for Blue and Yellow cards, later for Red cards, but it happens all the same.

At this point, i t is easy to figure out how many tokens it will cost to gain a level for that card - it will take 20 fused cards (5% * 20 = 100%).

EXAMPLE: If a BASE card is level 14 and now growing at 5% per red N card sacrificed, it will cost 30,000 tokens to gain the next level (20 cards * 1500 per card)

I can bring a Rare card to Level 10 for around 10,000 tokens (actually a bit less, but I'm simplifying). And I can sacrifice that level 10 rare card for 2400 tokens (1500 base, 900 for extra levels).

The level 10 rare gives either:

OFF-Color: 10 - 14 + 4 -2 = -2 bonus levels over the base growth rate of the card

Color Match: 10 - 14 + 4 + 0 = 0 bonus levels over the base growth rate of the card.

So if the card's base growth rate is 80% (a Rare +) then it will gain either 70% (for Off-Color) or 80% (Color Match) growth. I spend 12500 tokens and get easily 20,000-25,000 tokens of growth.

I should note that at some point after level 20, this stops being a good investment - eventually it becomes less expensive to use several N cards as opposed to a leveled up R or R+ Card.

Why Do you Raise your "Feeder" Rares to Level 10?

Well, that's the sweet spot for upgrading a level 20 BASE Card. If you do the math, you'll see that a Level 20 card costs 2100 to sacrifice an N Card. And that N card gives 5%. Giving you sacrificed card a level also gives you 5%. But to go from level 10 to level 11 costs 3000 tokens (usually) for a Rare - so level 10 is the last level that I see a cost savings.

Technically that is sub-optimal. I could raise the feeder card until it was almost worth what the 20 N Cards were worth, and so long as I gained a level I would be ahead. Likewise, if I am feeding a Rare to say... a level 15 card, it may not be cost effective to go past level 9. But, I find it simpler here to use a rule of thumb, and so I raise all feeder cards to level 10.

Why do some cards seem to get better faster than other cards?

When a card levels up, it can increase in stats in one of three ways: When comparing the Panther (3710/2520 at level 1) and Child+ (3710/2590 at level 1), the Panther levels up quickly, but the Child+ may eventually catch up at very high levels (40+). Another factor to consider is the max stats for each card which we do not know yet.
 * A fixed amount. For example: The Cheetah gains 25/28 each time it levels up regardless of level. The Cheetah gains 25/28 at level 2, 25/28 at level 3, 25/28 at level 4, and 25/28 at level 14.
 * A decreasing amount. For example: The Panther gains 59/40 at level 2, 58/39 at level 3, 57/39 at level 4, and decreases to 45/31 at level 14.
 * An increasing amount. For example: The Child+ gains 6/4 at level 2, 7/5 at level 3, 8/6 at level 4, and increases to 19/13 at level 14.

It appears that there are more cards that follow the decreasing method in the RED color, however there are examples of each type of growth in all three colors. Fixed amount seems to be the least common.

Rules of Thumb for those who Hate Math
 * Try to sacrifice weaker cards to better cards.
 * Sacrifice cards of the same color when possible.
 * If you are seeing very low growth, sacrifice N+, R, or R+ Cards you do not need OR cards of higher level you do not need.
 * Try to shy away from jumping multiple levels in a single fusion.