Do Buddhas and Bodhisattvas Exist in the World of the Three Realms?

The tathāgatagarbha is formless and without marks; it cannot pervade all of empty space. Only dharmas that have form and marks can be discussed in terms of pervading or not pervading. The tathāgatagarbha only pervades the five aggregates and eighteen realms of sentient beings and Buddhas. The five aggregates and eighteen realms encompass all dharmas within the three realms, while outside the three realms there is the tathāgatagarbha. Thus the tathāgatagarbha encompasses everything and pervades everywhere; wherever there is dharma, there is the tathāgatagarbha.

So, do the Buddhas and Bodhisattvas exist within the world of the three realms? This question then becomes quite obvious. Outside the world of the three realms, there are no five aggregates, no eighteen realms, and no dharmas whatsoever; only the tathāgatagarbha is a dharma outside the three realms. All Buddhas and Bodhisattvas possess the five aggregates and eighteen realms, and they never extinguish the five aggregates and eighteen realms. Only when a fixed-lineage arhat passes away at the end of life are the five aggregates and eighteen realms extinguished, and he is no longer in the three realms; likewise, only when the pratyekabuddhas enter nirvāṇa without remainder are the five aggregates and eighteen realms extinguished, and they are no longer in the three realms. But without the five aggregates and eighteen realms, there would be no existence of arhats or pratyekabuddhas at all; only their tathāgatagarbha would remain existing in tranquility.