Short answers, pulled from the story.
Line Corporation was originally founded on the 4th of September 2000, under the name Hangame Japan, as the Japanese subsidiary of South Korean NHN Corporation's online game community site Hangame. It was renamed NHN Japan in August 2003 and adopted the Line Corporation name on the 1st of April 2013.
Line Corporation held IPOs on both the New York Stock Exchange and the Tokyo Stock Exchange in July 2016. It delisted from both exchanges in late December 2020 ahead of its merger with Z Holdings.
In March 2021, Line Corporation merged with Yahoo Japan under Z Holdings, a SoftBank Group subsidiary. Naver Corporation and SoftBank Corporation each took 50% stakes in A Holdings Corporation, which held a majority stake in Z Holdings, the entity that now operates both Line and Yahoo Japan.
LY Corporation is the company formed on the 1st of October 2023, when Z Holdings absorbed its subsidiaries Line and Yahoo Japan. Line Corporation transferred its assets and businesses to LY Corporation through an absorption-type split and then changed its own name, leaving LY Corporation to operate the Line services.
Line Corporation operated a range of internet services centered on the Line messaging app. These included Line Music for streaming, Line Manga for digital comics, and Line Pay as a payments platform. In April 2021, the company also launched Line Bank, a commercial bank headquartered in Taipei.
The 2021 merger between Line Corporation and Yahoo Japan gave Z Holdings access to three markets where Line had a significant presence: Taiwan, Thailand, and Indonesia.