Can I react to the Effect of Dazzling Aurora?

Yes, you can react to the triggered ability of Dazzling Aurora.

According to the RiftJudge FAQ (ID 2639), Dazzling Aurora's ability is a triggered ability, and you can use reactions in response to that trigger. However, you cannot react to the gear being played itself.

Important Timing Nuances:

• Triggered Ability: Because it is a triggered ability, it uses the chain, allowing players to respond with [Reaction] cards.
• No Reaction to Playing: You cannot react to the act of playing the Dazzling Aurora gear itself.
• End of Turn: If Dazzling Aurora triggers at the end of a turn, the trigger is added to the chain, and players receive priority to respond with reactions before it resolves (FAQ 4615).
• Resolution: Once the trigger resolves and plays a unit, you cannot react to the unit being played, but you can react to any triggered abilities that unit might have upon entering play (FAQ 6408).