If I play Fizz and use his effect to play a spell from my trash, can I still play Darius Trifarian and get his effect?

Yes, you can still play Darius, Trifarian and receive his effect in that same turn, provided he is the second card played in that turn.

The Reasoning

• Defining "Played": In Riftbound, a card is considered "played" once it has fully resolved and entered the board (Rule 419.4.a).
• Fizz's Ability: When you play Fizz, Trickster, his "When you play me" (WYPM) ability triggers. This ability allows you to play a spell from your trash.
• The Second Card: Because you are playing that spell from your trash as part of Fizz's ability, that spell counts as a "played" card.

The Sequence

1. Play First Card: You play your first card of the turn (e.g., Fizz).
2. Fizz Resolves: Fizz enters the battlefield.
3. WYPM Trigger: Fizz's ability is added to the chain and resolves, allowing you to play a spell from your trash.
4. Spell Played: The spell from your trash resolves. This spell counts as your second card played this turn.
5. Darius Fails to Trigger: If you play Darius, Trifarian after this, he would be your third card played, and his ability will not trigger (RiftJudge FAQ #7884).

How to get Darius's effect

To successfully trigger Darius, Trifarian, he must be the second card played in the turn. You can achieve this by changing your sequence:

1. Play your first card (any card).
2. Play Darius, Trifarian as your second card.
3. Darius resolves, enters the board, and his ability triggers, giving him +2 Might and readying him.
4. Now play Fizz, Trickster. Even though Fizz is the third card played, Darius has already triggered his ability as the second card.

Summary: Darius only checks if he is the second card played that turn. If you play Fizz (and his spell) as your first and second cards, Darius will not trigger if played third. If you play Darius as your second card, he will trigger regardless of whether he was preceded by Fizz or any other card.