Yu-Gi-Oh! » Rulings Q&A

Does Ryu Kokki stop flip effects if they are warrior or spellcaster?

No, flip effects activate & resolve after damage calculation. If a flip effect needs the flip monster to remain on the field, the effect will stop being applied if destroyed by ryu kokki, such as Dharc the Dark Charmer. Dharc would resolve after damage calc, taking control of ryu kokki, but then @ the end of damage step, ryu kokki would destroy Dharc & return to its controller.