It can be used at any time during combat, even after combat damage has been dealt
The ETB damage keeps early boards under control, and if you cast it normally, youre left with a double strike creature that closes games quickly
In the past, the main argument against Hypergenesis is that it was more powerful than Living End because Living End can be hated out by graveyard removal like Leyline of the Void or Rest in Peace, although this argument is weaker now because of Glimpse of Tomorrow, which doesn't need the graveyard to win
When that resolves, the Twinflame will still be on the stack and you can use Dualcaster's enter-the-battlefield trigger to create a copy of it
Bolass Citadel There are only two outcomes when you resolve a Bolas's Citadel
The Saga of Sagas Often, when I do a design article about a set, I try to talk about all the aspects of the set