20 characters permanently lost Classic 5^85 hero
edit
statement will be coming out for soul exchange too once it’s live.
Probably this one
(I accidentally sacrificed my Hero/Troop! — Empires & Puzzles Help Center)
See also
Even if you just care about HA10 limited availability 5* heroes, that is 1:1, with an average of 3 per 420 days of HA10 while Soul Exchange and 3x RT20 is also an average of 3.15 ( lower tier ) to 1.575 ( upper tier ) limited availability heroes per 420 days
For the user base, as a whole, 420 days of HA10 results in 3x limited availability heroes ( these can be duplicates )
But you lose zero 5* heroes
For the user base as a whole, 3x RT20, for 420 days results in 31.5x 5* heroes, enough for 3.15x Tier 1, 5* heroes from Soul Exchange or 1.575x Tier 3, 5* heroes from Soul Exchange
But you sacrifice 30x 5* heroes,
If you get costumes for these sacrificed heroes ( looking at you Magni, and Marjana ) you may take years to get additional copies for alliance based events
Choose your 5* sacrifices wisely
FIN