Does Darius's ability trigger on himself when he is played?

Ruling: Yes, Darius's ability triggers on himself when he is played. In Riftbound, "played" means the full sequence of playing and resolving a card, so Darius is on the board and can trigger when he enters.

Nuances:

• This differs from some other card games where triggered abilities of permanents can only evaluate conditions once already on the board
• "When I'm played" abilities work the same way in Riftbound