The bodhisattva Maitreya is an important figure in many Buddhist traditions, where he is unanimously regarded as the buddha of the future era. He is said to currently reside in the heaven of Tuṣita, as Śākyamuni’s regent, where he awaits the proper time to take his final rebirth and become the fifth buddha in the Fortunate Eon, reestablishing the Dharma in this world after the teachings of the current buddha have disappeared. Within the Mahāyāna sūtras, Maitreya is elevated to the same status as other central bodhisattvas such as Mañjuśrī and Avalokiteśvara, and his name appears frequently in sūtras, either as the Buddha’s interlocutor or as a teacher of the Dharma. Maitreya literally means “Loving One.” He is also known as Ajita, meaning “Invincible.”
For more information on Maitreya, see, for example, the introduction to Maitreya’s Setting Out (Toh 198).