If you build a nether portal or use command to go the nether and die there, you can't go back there. 

I mean if you have a respawn anchor then its fine but if you dont and you die there, you slaw back at the over world and can't go back to there!!

If you type /kill @p.  It won't work

If you leave the game and join again then, you will start inside a players body. The player will have your skin and your name. If you type /kill @p again it will kill the player but you won't be able to move. If you leave and join again you won't be able to move alongside you won't be able to break or place blocks!!

Regarding my views please fix this. All my hard work gets destroyed because of this