大毘盧遮那成佛經疏 10.164

10.164

此五字是世明妃種子字，雖是佛化，相同世間，謂天等也。遍一切所有明妃，隨取其一。

These five syllables are the bīja syllables of the worldly vidyārājñīs. Although they are transformations of the Buddha, their marks resemble the worldly, meaning devas and so on. Among all vidyārājñīs that exist, take any one at will.