When Regenesis Lord is special summoned, players can set a Regenesis Spell/Trap from the deck, which makes it an incredible combo starter that allows players to continue their plays after they are interrupted
Cards to your characters and your opponent can fend off your attacks by countering (discarding character and event cards from their hand, as opposed to playing them, in order to booster their defensive power) or using a blocker to take the attack for their leader
This is nice for Commander or key legendary stuff like Akroma
That last part is about to change, sure, but it still feels as though we could have had a day and night themed deck given that this mechanic is new to Midnight Hunt too, despite it basically being a more logical way of explaining the Werewolf transformation, and one that we hope causes an errata onto old Werewolves where possible
It can't take advantage of cards like Zur the Enchanter, and you can't cheat it out with cards like Brilliant Restoration (well, you can, but you still have to unlock the doors)
If the spell has multiple targets, a given creature must be a legal target for all of them or else a copy wont be created for that creature