A 5000-year old vegan dragon was living peacefully when one day a young girl showed up in his cave. She offered herself as a sacrifice in order to gain favor for her village. He played along as the great "Jaryuu-Sama, the Demon Lord's Army Leader" in order to get rid of her. However, his little white lie awoken her hidden powers and his peaceful life suddenly ended.
Alternative:
齢5000年の草食ドラゴン、いわれなき邪竜認定; ~やだこの生贄、人の話を聞いてくれない~; Weak 5000-Year Old Vegan Dragon; Yowai 5000-nen no Soushoku Dragon, Iware naki Jaryuu Nintei; Yowai 5000-nen no Soushoku Dragon, Iware naki Jaryuu Nintei - Yada Kono Ikenie, Hito no Hanashi o Kiite Kurenai