I'm a Behemoth, an S-Ranked Monster, but Mistaken for a Cat, I Live as an Elf Girl's Pet, Vol. 11 (manga) — Nozomi Ginyoku

After defeating the Four Fiends and defending the elf homeland, Aria and her friends receive a new request from a pair of visitors. Mai, a time traveler from the future, and hero Ciel ask for their help in suppressing the demon lord Belphegor, who has emerged from the world of the future. Thus, the party crosses the ocean and arrives in the Kingdom of Urscula!