Alien Rivers (リヴァーズ星人 Rivāzu Seijin) is an alien that first appeared in Ultraman Taiga episode 1 "Buddy Go!." One individual appeared, named Kawazu (河津 ). They have the appearance of a human, but it is unknown whether it is their original appearance or mimicry.
Kawazu was a scientist who specialised in protecting endangered kaiju across space-time. He requested EGIS to protect and escort Baby Zandrias, who was targeted to lure out Young Mother Zandrias, who was then to be used as a tool to demonstrate of Zegan's power during the Villain Guild's Monster Auction. Alien Magma temporarily robbed Baby Zandrias from him, but in the end, once both mother and child were safe thanks to the help of Hiroyuki Kudo and Taiga, Kawazu left the Earth via spaceship, taking both Zandrias into space with a tractor beam.
- Kawazu's name is a pun on his species' name. The word 河 (kawa) means "river". The word 津 (zu) can be substituted for the katakana ズ, which is often used for denoting plurals in Japanese Romanizations. If his whole name were to be written in katakana (カワズ), it would translate to "Rivers".
- Kawazu is so far the first "first" monster/alien to appear which is a human lookalike and does not, as far as we know, have a true form with the human appearance being it.