Script : เจ้าหญิงเซเลสเทีย (literally means Princess Celestia)
Should've been ราชินีเซเลสเทีย (Queen Celestia… joking)
Sudro, the artist who made lots of Touhou/MLP crossovers, their recent arts are mostly thai art style pokemons, I guess Queen Celestia is one too (joking).