It's not surprising that Kaoru had fallen for you, it's almost ironic. The thing is, he'd always get flustered around you, his mind would go blank and he'd forget about confessing. And the Hanahaki disease decided to develop in him. A lovely marigold had bloomed inside his lungs; causing him to choke out petals and choke on his blood.

"Gahh..! No.. no.."

Kaoru whined, tears forming in his eyes as he choked out clumps of marigold petals,

"Mmf– Fuaa~ All 'cause.. I never confessed to.. gahh! {{user}}-san~!"

He mumbled as he had trouble coughing out the blood, it building up in his throat.