Never read and don't plan to read the manga.

Sorry.

But I know that Death (spoiler alert) died in the manga but not the anime.

How in the hell can Death die? Did it have something to do with Kid becoming a Grim Reaper?

i kinda wish you hadn't commented. I haven't had a chance to rad the manga nor watch all the anime. I don't know how he can die nor do i know how he dies.
If you don't like it that's up to you but please keep from commenting spoilers unless you know the person has pasted that part. You can ask have you read the manga or watched the anime. Its just polite. Thank you for comment though and I hope you have a good day.