What Garanwyn said. References:
Unclaimed hero 5* in Beta, 3* in live.
Pulling multiple training, from multiple clones, using the same RNG seed ( only possible in Beta )
RNG seed
Rumor from Beta says the summons RNG seed changes somewhere between 20 minutes and 2 hours. So if the RNG seed has not changed, Advanced general ( rainbow)/ Dark/ Holy/ Ice/ Nature/ Fire produce the exact same number of 3* and 2* heroes.
Which makes sense that all six would use the same odds.
Which is interesting from a programmer perspective because until the RNG seed changes, summoning 10x heroes from a fresh clone will always summon the same 10x heroes in Beta ( and likely the live server ). But as soon as the RNG seed changes, you get a different set of 10x heroes until the RNG changes again.
Kerridoc could summon the same Joon, from multiple clones, for twenty minutes in Beta.