1. Mahasthamprapta Bodhisattva is in Sankrit and is a male fiture.
2. In chinese, is a female figure and the name in chinese is Da Shi Zhi Bothisattva. In vietnamese Dai The Chi. Very much like chinese lol of course.
3 Mahasthamprapta Bodhisattva is one of the two high stage Bodhisattva in Amitabha Buddha's world, often He is on the right side of Amitabha Buddha where as Avalokitesvara Bodhisattva is on the left.
I have read a sutra in vietnamese called "Kinh Bi Hoa". I don't know if they have it in english yet, but this sutra basically Shakyamuni Buddha taught about the past lifetime of Amitabha Buddha, past lifetime of Avalokitesvara Bodhisattva, past lifetime of Mahasthamprapta Bodhisattva, past lifetime of Manjusri Bodhisattva, and past lifetime of Samantabhadra Bodhisattva.
And In this sutra, Shakyamuni Buddha taught past lifetime of Mahasthamprapta Bodhisattva was a prince. Amitabha Buddha was a king and father of all those prince. In that sutra, Shakyamuni Buddha also taught about the reasons of how Mahasthamprapta Bodhisattva achieve Bodhisattvahood and also the prediction future Buddha of Utmost Bliss. Shakyamuni Buddha taught, after Amitabha Buddha entered Nirvana, Avalokitesvara Bodhisattva will attain Buddhahood and become Buddha replace Amitabha Buddha in Utmost Bliss world. The name of Utmost Bliss world will also be changed. And after Avalokitesvara Buddha enter nirvana, Mahasthamprapta Bodhisattva will attain Buddhahood and become Buddha replace Avalokitesvara Buddha in that world and that world will have a different name.
I wish very much the sutra is available in english. I will try to find it.
In Sutra of Contemplation of Amitabha Buddha. Shakyamuni Buddha also taught about Mahasthamprapta Bodhisattva and described him a little bit. In Shurangama sutra on chapter Mahasthamprata Bodhisattva, Shakyamuni Buddha also taught a little bit about him.
Namo Amitabha Buddha.
Namo Avalokitesvara Bodhisattva.
Namo Mahasthamprapta Bodhisattva.
Namo Amitabha Buddha.