Anime Question : R.I.P !!!!!!!?

No, don't get it wrong. This not means me or anyone who like to do this stuff will not doing it again. It's just about character who I think is deceased but still being mention in the anime. Ghost will be included too. 1pt for character's name and 1pt for anime origin.

1. 6 versus 1 is never a fair battle. He managed to leave a message on a frog before he passed away.

2. A wearer of cat mask gets his chance to leave the underworld for a day and fight his adopted grandson. Since they learn from the same master, their techniques are quite similar.

3. They seem like twins, but one of the girls is actually a clone. She sacrifices her life so the other twins can survive from incurable disease. The other twins absorbed her soul. BTW, they are devils.

4. He is skilled in sniping, and his robot also specializes in sniping. After he died on battle, his twin takes over his job, or rather his position on the team.

5. A ghost who is placed at the first seat in the class for 60 years. That place stays vacant and anyone who placed beside her always felt chills.

6. An original owner of armour that main character has. She sacrifice herself to protect the main character who is heavily wounded by using the armour to the maximum limit, which causing her life. The armour only activates with a song.

7. Someone who wears comical lion head mask and frequently talks to the main character when she’s young. He motivates the main character to become astronaut and go into space.

8. She is a mother of a girl who is rich and also an otaku. Someone said that the girl’s butler has a same face like her mother.

9. Another mother of an otaku. She once gone back her home and tried to stand together when her daughter and husband taking pictures, but she is being mistaken as an evil spirit instead.

10. A wife of delinquent (when he is high school). His husband supports her from making a drama club in high school. Even though had risk if she’s getting pregnant, she still want to born the baby. In the end, died by giving birth of her daughter.

Awaiting for answers!!!!!