When Irresistible Faefolk goes to the battlefield, am I attacking or defending?

When you move Irresistible Faefolk to an unoccupied (uncontrolled) battlefield, you are the attacker, and the enemy unit you move to that battlefield with its ability becomes the defender.

According to Rule 459.2.b.1 and established RiftJudge FAQs (such as #10101, #9828, and #9714), the determination of attacker and defender designations is based on which player applied the "Contested" status to the battlefield first:

1. Move: When you move Irresistible Faefolk to an unoccupied battlefield, you are the player who applies the "Contested" status to that battlefield. This makes you the attacker.
2. Trigger: Irresistible Faefolk’s ability triggers. When it resolves, you choose an enemy unit and move it to that same battlefield.
3. Combat Transition: Because units from opposing players are now present at the contested battlefield, the showdown transitions into a Combat Showdown.

Even though your ability moved the enemy unit into the combat, you remain the attacker because you were the one who initiated the combat by applying the "Contested" status to the battlefield first.

Note: If you move Irresistible Faefolk into a battlefield that was already contested by your opponent, your opponent is already the attacker, and they remain the attacker regardless of your ability.