Quick Transmigration: Irresistible Beauty - Chapter 215: White Lotus Transfer Student (45)

He is a young man without a spirit root. It is believed that this denies him the chance at cultivation. However, a mysterious lady imparts a Supreme Demon Classic to him and from then on, he starts his path of cultivation.
He undergoes a total transformation to emerge as the most fearsome and powerful fiendish demon in his era, that even immortals and fiends are fearful of him, and saints are at his beck and call.
Mastering the Supreme Demon Classic is the turning point in his life. He is able to unleash his immense and divine power from within, illuminating the entire universe!

- Description from Novelupdates

The Void Demon Realm invades, and Shu Feng awakens to become a Spiritualist, coming into contact with the true reality of the world.No one knows that he has a Mysterious Base within his body which could use Void Demon's power to enhance his body.

The universe is big, and Hayden’s about to invade it. Being drafted into a demon army wasn’t on Hayden’s bucket list. But when his soul is shoved into a human soldier on the eve of a new invasion, it’s not exactly like he can appeal the decision. Surrounding Hayden are demons, excited and ready. For them, the invasion promises a feast of souls and new growth. Their target? Berlis — a sword and sorcery realm straight out of classic fantasy. Hayden’s human status puts him at the bottom of the totem pole, meant to be cannon fodder that soaks up damage and dies first. But as he plunges into the carnage, he’s learning that he was born for the madness. Readers can expect: + Grimdark action and violence + Fighting, lots of it + Multiple worlds and magic systems + Slow burn

I became the childhood friend of the protagonist in a novel. The childhood friend who died from taking drugs.