The weakest job becomes the strongest in the world with past life knowledge is a Manga/Manhwa/Manhua in (English/Raw) language, REINCARNATION
series, english chapters have been translated and you can read them here. You are reading chapters on www.kissmanga.in fastest updating comic site. The Summary is
A young wizard dominates with the knowledge from his past life, breaking through level limits!
The strongest wizard, Roy, is reincarnated into the future as a young boy, Yuug. However, magic has declined since then, and wizards are considered the weakest class.
With the knowledge of magic from his past life and his extreme-level abilities, Yuug embarks on his second life’s adventure…
