Goat format ruling
Strike Ninja

Card effect (current official text)(Quick Effect): You can banish 2 DARK monsters from your GY; banish this face-up card until the End Phase. You can only use this effect of "Strike Ninja" once per turn.
Rulings
- You cannot activate Strike Ninja's effect during the Damage Step.
- Strike Ninja is a Multi-Trigger effect so you can chain it to another Spell Speed 1 or 2 effect and can activate it outside your Main Phases, even during your opponent's turn (but not during the Damage Step).
- You can only activate Strike Ninja's effect when Strike Ninja is face-up on the field.
- "Strike Ninja’s" effect only applies while "Strike Ninja" is face up on the field.
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Goat forum — sourced change requests get reviewed.