The earliest point in the turn where you can cast an instant is during the upkeep, right after beginning of upkeep triggers have gone on the stack
Card-wise this one works well replicating the idea of a Ghoul pack, with the rad counters working to represent the radioactive conditions Ferals like to make their dens in, which tends to lead to the next card in this review
If youre looking to make a quick decision , go right to the Rayvol Premium Binder it has a classic black design, costs ~$24, can store 504 cards, and comes with binder sheets so youre ready to go!
The ideal scenario is to start using the Leader effect at turn 4, and through Black Moria s Ramp effect, we gain back the returned Don, making sure we continue the pressure on upcoming turns
If only it wasnt worded attacking you so you could use this in response to any combat, not just creatures heading your way