User blog comment:Halo1081/Chapter 128 and forward/@comment-4911196-20150302030909

From my Point of View there are several revelations regarding to Koro-Sensei which was still suspected.

Kayano was actually Yukimura Aguri's younger sister, Yukimura Akari and i was thinking that Yukimura Aguri has a double job, one as a teacher of Class E and second she was a scientist who conducting a research on Koro-Sensei before the research facility destroyed by Koro-Sensei, killing Yukimura Aguri while her sister took the tentacles as a specimen to vow vengeance for Koro-Sensei.

It seems Yukimura Aguri was also a researcher and scientist as i read several fields of background when Koro-Sensei reminded of the past include the debris of destruction that confirms both Koro-Sensei and Yukimura Aguri was from Research Facility.