We know in one of the episodes while Goku, Vegeta, Whis and Beerus sat down to eat, Whis stated that there were 18 Universes before and Zeno erased 6 Universes while he was in a bad mood.
After the Zen Exhibition match, we know for a fact that if Zeno were to erase a universe, even the gods, The kaioshin and hakaishin would also be erased. We also know that the angels are not related to the universe and their duty is to only serve the god of destruction, which is again mentioned by Whis when Beerus questioned as to why he wouldn't get erased.
It was also mentioned by Shin during the Future Trunks arc that if Beerus were to die, Whis were to leave the universe as his sole duty is to only serve Beerus.
Based on these events, shouldn't there exist 6 more angels of the erased Universes? Why aren't they watching the tournament of power (When the exempted universes are watching the same)? We know these angels don't cease to exist once their universe is erased as we see some of the angels of the erased universes seated and watching the tournament of power.
What are your thoughts on the same?