Thus begins a series of four Saṁyuttas on various nonhuman entities.

The “dragon” (nāga) is a powerful (Bu Pc 51:1.4) serpentine (SN 1.37:7.4, Cp 20:1.2) entity with fiery breath (SN 3.1:8.2), bearing magical gems (Bu Ss 6:1.3.2, Ja 253). They dwell underground (MN 23:2.39), or in the ocean (Ud 5.5:17.1), or in the mountains (SN 46.1:1.2), guarding treasure (Ja 506) that they may have stolen (Kp 8:4.3). They may be man-eaters (SN 6.4:9.2) or protectors (Ud 2.1:2.2), and occasionally had to be engaged in magical combat (Kd 1:15.2.3), Bu Pc 51:1.4). They are color-changers (SN 3.1:8.1, Cp 13:3.1) and shape-shifters who, though they revert when they sleep, can temporarily take human form (Kd 1:63.1.1), even for the purpose of intimate relations (Bu Pj 1:10.14.1). The line between the supernatural entity and organic snakes is as fluid as a serpent’s form; dragons act as the leaders and protectors of all snakes (Kd 6:23.13.5), while poorly behaved dragons may be banished to a snake’s existence (Ja 304). Powerful and feared though they are, they are still no match for the cruelest of predators, man (Ja 524). For a history of the word, see SN 46.1:1.2.

These four are defined at MN 12:32.1; see note there for Vedic and Jain sources. | The Dhammic import of this idea is that even such powerful entities are born, and hence are subject to old age and death.