Edison format ruling
Ryu Kokki

Card effect (current official text)At the end of the Damage Step, if this card battled a Warrior or Spellcaster-Type monster: Destroy that monster.
Rulings
(1) If this card battles a Warrior or Spellcaster-Type monster, destroy that monster at the end of the Damage Step.
- The (1) mandatory Trigger Effect activates in Substep 7 - End of the Damage Step.
- If Ryu Kokki was destroyed by battle, this effect still activates.
- The monster's current Type must be Warrior / Spellcaster in order for this effect to activate.
- VS. Goyo Guardian: The effects of Goyo Guardian and Ryu Kokki form a single chain during Substep 7 of the Damage Step when they battle. Kokki's mandatory trigger effect will be Chain Link 1 [REF].
Rulings data courtesy of Format Library — formatlibrary.com. Spotted an inaccuracy? Flag it in the Edison forum — sourced change requests get reviewed.