Tadashi's uncle. He is an inventor and has an assistant, Ms. Yoshiyama (manga only). He tries to figure out what makes the fish move. He once smelled a human corpse, relating the stench to the stench of the creatures.   (Source: Wikipedia) 

The floating smell of death hangs over the island. What is it? A strange, legged fish appears on the scene... So begins Tadashi and Kaori's spiral into the horror and stench of the sea. Here is the creepiest masterpiece of horror manga ever from the creator of Uzumaki, Junji Ito. Hold your breath until all is revealed. 
Something's rotten in Okinawa... 
(Source: Viz Media) 
 
Included one-shots: 
Volume 2: 
Daikokubashira Hiwa (大黒柱悲話, The Sad Tale of the Principal Post) 
Amigara no Dansou no Kai (阿修羅断層の怪, The Enigma of Amigara Fault)

Something in Okinawa reeks, and it isn't long before Kaori and her friends realize that the smell is coming from dead fish, which are walking out of the sea. The fish are fused to metal legs and are infected with a disease contractable by humans that was invented as a weapon by unknown sources. After what happens to Tadashi, Kaori finds herself in a new world very much like the old one but with the stench of death. 

Sazuku Koyanagi