Both Jester's Cap and Mask were sought-after cards, although good players quickly learned that the Mask was actually pretty terrible
A nice thing about this commander is that its ability works whenever you attack with any creature, so its ready to go as early as turn 4-5
I am already planning to try Vivi out in my Izzet prowess deck, which will either pop off, or get removed on sight
The biggest difference is that Rayami wants those cards to die on the battlefield, so sacrifice outlets are important, whereas Indominus Rex wants those cards in your hand, which it can then easily refill with its own ability
Then you can spend six to drop for free two critters in your hand
What other heroes and creatures would you like to see represented in the upcoming Forgotten Realms set