They were serious when they said they’ll release new information of the drama every Thursday leading up to the first episode. Today they announced that a spin-off drama called “Todome no Parallel” will be released on hulu, and each episode will be streamed right after the main drama ends its broadcast every week.
In the main drama, Outarou dies after being kissed by the mysterious woman, then time leaps and wakes up 7 days in the past, in a new (parallel) world. He repeats this every week as he gets killed again and time slips to another parallel world. After each episode airs, the spin-off episode for that week will stay in the same world where Outarou dies. It will start from the moment he dies, and shows what happens after his death. The second half of the PR video below shows the spin-off portion.
Todome no Parallel @ hulu:
Trailer (Main drama + Spin-off):
— トドメの接吻［公式］ (@todome_kiss_ntv) December 27, 2017
Kento’s comment (as posted by hulu):
— Hulu Japan (@hulu_japan) December 28, 2017