A hero is fully levelled with special skill raised to 8/8 and yet, even though the costume has also been levelled up, the special skill remains far from being maxed.
As a result the costume bonus of the hero remains at levels like 3 and 6 percent rather than 5 and 10 percent. The costume further can’t gain from limit breaking or from embleming.
The reason this happens is that, while feeders give 2.5 times as much experience to a costume rather than a non-costume hero, they don’t seem to add to the special skills of costumes at such an increased rate.
This raises a question as to which feeders are best used where.
So here’s some reference to hero experience gain from feeders.
When feeding to the same colour:
a 1* feeder gives 180 experience (or 450 xp to a costume)
a 2* feeder gives 468 experience and
a 3* feeder gives 756 experience.
On levelling up, this from the fandom wiki:
Condition
Chance of Rank Up
Off-Color Hero Sacrificed
+1% chance per star of sacrificed hero
Same-Color Hero Sacrificed
+2% chance per star of sacrificed hero
Same-Named Hero Sacrificed
+25% chance
Leveling Hero is Maxed, but Special Skill is not
5x increase in above chances (just 100 % for same-named hero, no further adding up possible like “200 % – two levels at once”. Also does not apply for leveling maxed Costumes via same hero)
So a 2* hero will give a 4% chance of increasing a special skill but a same named 3* hero will give a 25% chance of increasing special skills.
For this reason it seems like, even if you haven’t fully levelled the non-costumed side of the hero, the most efficient use of duplicates will be to feed them to the hero’s costumed side.
I don’t believe you have the 25% chance of increasing your costume skill when you use a regular hero. That is if you are maxing your Belith costume and use Belith, it’s only a 6% increase. I just tried that with Grimm costume and feeding a Grimm hero only give 8%.
But if you feed the same costume (Belith costume), I believe it’s a 50% increase. At least that’s what happened when I just tried leveling Vanda costume with another Vanda costume.
When it comes down to it, if you want to avoid that situation, the best option of leveling 3* costumes is just to use 1* feeders of the same color. Doesn’t always work, but in my experience, I usually end up with at least 6/8 on the special.
Once the costume is levelled up, you only need 1 spare of the same costume to raise the special skill level. I’ve done this a few times. e.g. costume Valen’s special skill was at 7/8, I fed him an extra costume Valen and his special skill went up to 8/8
Yes, I did specify fully levelled costume. I wouldn’t bother with feeding spare costumes unless the special skill just wouldn’t level with normal feedings of 1* heroes. Feeding spare costumes comes in only if you’ve done everything else and still can’t finish the special skill off.
It is late, and I am tired so maybe I don’t understand what the real point is here, but…
Leveling a costume goes much faster than leveling the hero. This, of course, is due to the bonus feeders get when feeding the costume. And, there is another bonus in that costumes can be fed. AND, there is a same element bonus for both feeders and costumes.
However, when players try to speed through the costume process, they often leave the costume’s skill level languishing as is shown in the Belith card above. I try for a balance. No 4*, and only a couple 3* max in each 10-lot of feeders.
TL;DR: In my view, optimizing three star costume feeding uses only one star feeders until the costume is at 3.50, and then you can add in two stars, dupe heroes/costumes/other high value feeders to get the SS to 8/8. Anything before that is inefficient.
My strategy is to feed only 1*s to three star costumes, as they level so quickly. It’s a balance between the likelihood of the SS increase and the length of the ‘runway’ to get them to 8/8.
If I have multiple costumes (it doesn’t matter if they’re leveled or not) of a particular hero, I wait until the costume is at 3.50, and then feed them the dupe costume. Not the dupe hero, the dupe costume. This will tick your SS up a notch. If you feed them the costume before they’re at 3.50, you get a 25% chance of SS increase, and it’ll eat up a huge amount of the leveling runway, pushing you to 3.50 much faster. Which in this case is a disadvantage, because you’ll not be at 8/8 and will still require additional feeders.
I think the most efficient way of raising special skills for costumes is feeding their duplicates to them. I’m yet to see if feeding out of costume dupicates will have the same effect, but, SCIENCE!
I’ll do more tests when I’ve sets of four duplicates to feed.