For example, orthodox cultivation techniques are akin to a plant's "photosynthesis," where the energy source is clean and pure, but the downside is low efficiency.
The Demonic Tao techniques, on the other hand, are like "herbivores" that accumulate energy rapidly within the body by directly consuming "plants," aiming for a swift increase in cultivation level.
The Blood Fiend Sect's "Bloodthirsty Skill" enhances one's cultivation level by absorbing the energy within blood qi.
The Hehuan Sect's "Pure Essence Skill" enhances cultivation level by absorbing the yin energy or yang energy of the human body.
Without exception, all involve obtaining energy by "eating grass."
The advantages of these techniques are their fast cultivation speed; the disadvantages are unstable foundations, patchy spiritual power, prone to hitting bottlenecks, or getting struck down by heavenly tribulations.