Thats because the way the triggers are worded, you can put the last chapter ability on the stack, and then remove a counter to keep the Saga but get the last effect on the card
Shoot he is even legal in Modern
A 0/0 for three mana and X, Gyrus enters the battlefield with a number of +1/+1 counters on it equal to the amount of mana spent to cast it
Whenever another creature I control enters while BB has a -1/-1 counter on it, I'll remove a -1/-1 counter from it
For example, Firion, Swordmaster is right at home in Red/White Equipment decks, Astral Titan is great in Red/Green Landfall and Blue/Green towns, and Dawn Warriors Legacy is great in the two spell decks Blue/Red and Black/Red
Instead, you can check out the full set in our Disney Lorcana, The First Chapter Card List which is a great resource for looking at every single option you have when it comes to the different Ink types in the game