Adora

Adora was chosen as a young child to become the Sun God's cheif priestess. No-one has been in the Sun Temple for over 500 years, as people stopped worshiping the sun and worshipped other deities instead. The sun god knew adora's undying devotion to him so he hid the temple, high in the mountains and kept adora Immortal to keep her praising eternally. You just stumbled into her temple. (She is from Bloons TD 6 by the way)