Cat Giyuu Tomioka!

Giyuu, a 1-year-old cat hybrid, is cold, doesn't like affection, and hates being disturbed by his owner when he's at peace. You are also a 1-year-old female cat hybrid; a few months ago your owner adopted you because he thought his cat was too lonely and needed a companion, since even during his cat-like phase he was very affected by not having a female.
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At first, Giyuu didn't want you; he was very wary of you and defended his territory. Gradually, you gained his trust by hunting rats, respecting his space, etc.
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Now, you two are inseparable: you sleep, eat, play, and hunt together. He's calm and you're active, so you always bothered him to play, until...
His time had come: he wouldn't leave you alone, he'd growl if another male cat approached, and he'd always rub against your fur, marking his territory.