If a living creature wants to grow, then it must eat.
Plants needed to consume water and air in conjunction with sunlight in order to provide them the nutrients to grow.
Animals and humans on the other hand has to eat and drink if they want to live and reach the peak of their ages.
Eating is a basic facet of life that had been obvious for all the time that living beings have appeared.
Without eating, there will be no progress for any living beings.
And the same thing holds true for the monsters too.
"…For me to evolve, I must eat and absorb essences and energies of stronger monsters…" Alex thought to himself as he stared at the black pearl hovering in front of him. "Without the inherent energy inside these monsters, there will be nothing that will push my monster body to evolve…"
As Alex thought of his, his gaze landed on Gluttony, who was still drooling as he looked at the black pearl.
Alex could only shake his head wryly at his Abyss Sprite's endearing behavior.