Tips for Upgrading Survivors

Upgrading a survivor increases his Evolution.

A survivor has both Evolution and Level. Level increases the survivor's attack and defense values. Evolution increases those values plus it increases the survivor's skill by either increasing the percentage chance the skill will happen in a battle or by increasing the boost that the skill gives. A survivor can only be upgraded a maximum of 4 times.

To create the ultimate survivor, you should first fully train the survivors you will be upgrading (see Guide to Training Survivors). However this is costly so should be done for Rare and Epic survivors that you acquire.

Recommended Upgrade Strategies
Using these upgrade techniques gives you a survivor tha survivor
 * 1) Upgrade using the max-trained Evo3 survivor and the max-trained Evo1 survivor
 * 2) Max train the Evo4 survivor

Option 2: Training 7 times using 4 survivors
This option requires a lot of training materials and results in a more powerful survivor (this is the 4-7 option in the Max Training Analysis). Start with four survivors.
 * 1) Max train two Evo 1 survivors.
 * 2) Upgrade using the two max-trained survivors.
 * 3) Max train the resulting Evo 2 5555555555555555555555555555555555555555555555555555555555555555555555555555555555555survivor and max train another Evo 1 survivor
 * 4) Upgrade those two max-trained survivors
 * 5) Max train the resulting Evo 3 survivor and max train your last Evo 1 survivor
 * 6) Upgrade those two max-trained survivors
 * 7) Max train the Evo 4 survivor

Option 3: Training 7 times using 8 survivors
If you can acquire 8 of the same survivor, use the following upgrade steps. This requires fully training seven times and results in a survivor that is 99.7% of the absolute maximum he could be (this is the 8-7 option in the Max Training Analysis). Note: if you want a survivor that is 100% best, use fully train Evo 1 survivors in step #1 above. But this is extremely costly of training materials because over the entire process you will have to fully train 15 times instead of seven times and only improve the end result by 0.3%.
 * 1) Upgrade using two level 1, Evo 1 survivors to create an Evo 2 survivor. Repeat this until you have four Evo 2 survivors.
 * 2) Max train all four of your Evo 2 survivors.
 * 3) Upgrade using two of the max-trained, Evo 2 survivors. Repeat this for the other two Evo 2 survivors. You should now have two Evo 3 survivors.
 * 4) Max train these two Evo 3 survivors
 * 5) Upgrade using the two max-trained, Evo 3 survivors.
 * 6) Max train the Evo 4 survivor.

Comparison of Sacrificing 4 and 8 Survivors
Most people upgrade a survivor by sacrificing an Evo1 survivor to increase the main survivor, irrespective of the evo-level of the main survivor. Another option, however, is to use the same evo-level for both the main survivor and the one being sacrificed. This leads to an even stronger result because the power of both sacrificed survivors is higher.

The following upgrade tree shows the increase in power when upgrading Sofia the Civilian using just four Evo1 survivors and using eight survivors to create the stronger Evo4. The bottom number in each bubble shows the attack value.



Note that at Evo3, attack level is higher by 15 points (at 2148 compared to 2133) and at Evo4, attack level is higher by 58 points (2839 compared to 2781).

Notes from a forum post
The following was taken almost verbatim from funzio.com forum post:
 * The idea is that each unit at max level contributes 10% of its stats to the next evo. This has diminishing returns on repeated evolutions. The Evo2 will then carry 11% to Evo3, 1% of that being the power carried over from Evo1 max. At Evo4, max leveling the Evo1 in the first stage only gives ~0.1%. It's not exactly like that, just an example. The real percent is over 10% because you have two survivors both giving 10%, but also subtracted by the 5% normal carry over of an unmaxed, level 1 survivor.


 * 4-7 : The 4 means number of survivors you start with, the 7 stands for how many times you have to max level them. 4-7 is maxing every card (including the final Evo4) so it's not that hard.


 * 4-4 : You start with 4 cards, and max level the last 4 times, choosing the biggest survivor from a pair if you can't max both. In this example, you upgrade to Evo2, then level Evo2, upgrade max Evo2 with lvl1 Evo1, level Evo3, level last Evo1, upgrade to Evo4, level Evo4...done. You've leveled a total of 4 cards, working backward from Evo4 choosing the biggest ones.


 * Again, the difference between 4-3 and 4-7 is likely 300-400 points for Evo4 Legends. I made sure of this by checking with alliance mates before deciding to use 4-3 to fill out my party. The most important ones to level are the final two survivors before the upgrade to Evo4 since they both pass the full 10% of their stats to the final evolution. The cumulative stats given before that are around just 1%.