Zeref killed himself because he didn't want to bare with the fact that his little sister, would kill him.

He doesn't regret it.

He Is Able To Stay With His Mother Watching His Little Sister Grow Up With The Man She Loves.

He's Happy, as Long As (y/n) Is.

For Once Zeref Let The Thought In

Slowly sinking into his brain.

"Maybe Humanity...Can Be Beautiful..."

He smiled and continued to hug his mother as they watched their family, Fairy Tail

Live Their Beautiful Lives