System: Evolve by Devouring After Reincarnating as a Snake

[Dual male leads + System + revenge + master and disciple + the top is undecided; it depends on how the plot develops and what the author was eating at the time (probably an older top, with the master as the top)] Bai Ting was reborn as a black snake, bound to a Devour and Evolve System, and set on the path to becoming a dragon. Sadly, he was betrayed and fell into the Abyss of Demon Burial. An Immortal Emperor's soul saved him, and he became the emperor's disciple. Jiang Wuchen, courtesy name Zihan Shuang, was once the youngest Immortal Emperor, known as Lord Fugu. Betrayed by his sworn brother, he fought to the death and self-destructed, leaving his soul scattered. Fortunately, his remnant soul escaped into an ordinary jade pendant, which fell into the lower realm and gave him a chance at life. Later, he came across a black snake that had fallen into the abyss. Moved by the snake's plight, he felt a kinship with him, so he rescued the snake and took him as his disciple. The first small section is just a transition. The later story is still modern-day: an invincible, cathartic revenge novel.