About Sell Champion

Heart

I have Thor (Ragnarok) ☆4 & ☆3.Should i sell Thor (Ragnarok) ☆3 or i save it?
Yes always do that,example i have Yellow Jacket ☆2 then i got Yellow Jacket ☆ 3,Then I Sell Yellow Jacket ☆2 because YJ ☆3 is more powerful

Polderpommie

You can. But I wouldn’t. Every time you dupe a champ, you get shards and iso. When that champ reaches its max signature level, you get a crystal that will mostly give you more shards still, so you build your crystals twice as fast. Selling will give you less.

Gwendoline

You should never sell a champ. Keep them. You'll get rewards for duping them and at some point they are maxed and give double the shards.

On some rare occasions you need them, like the 2* arena in december. On less rare occasions they are useful in arena. Even if you don't do arena on a regular basis, you might do them at a later point. Even if it's just a quick unit run, the more champs, the easier it will be.

Hammerbro_64

Don’t sell them. You lose rewards that way