Like with a lot of particularly unique minded individuals, it’s always a mystery as to what goes on in the head of such creatives as del Toro. The extremely complex and unique nature of his world building and character creation makes a lot of people wonder just what’s going on inside his head.
However, when it comes to the monsters that he presents in his films, it’s very clear that his inspiration doesn’t come from the abstract. Despite their alien nature, the monsters in his films always have quirks or distinctive traits that make them undeniay human.

The Pale Man, from Pan’s Labyrinth. The symbolism with the eyes on his hands is our first starting point; he is only able to see that which is reaches for and seeks to possess. If our protagonist fails to abide by the rules and takes any of the bounty before her for herself, he becomes enraged and will threaten to kill her for it.
The creature is very distinctly a personification of greed and ambition; likely reflecting the protagonists father who relies on such traits to survive. The existence of the character at all is a criticism of humanity itself and yet the creature is undefeatable; perhaps as another warning that we as a species are unable to overcome our selfish desires.
However the representation of human traits are not only negative.

As well as in popular films such as Hellboy one of del Toros more recent films shows that even something monstrous is capable of love and emotion regardless of its nature.
The creature is chained up, experimented on, hurt by human captors for the entirety of the film. And yet it still finds softness within itself to fall in love with a human woman. The director himself stated that the character was intended to show the fluidity of love (hence, Shape of Water) and how even something seen as so taboo and otherworldly is still worthy of the affection that we bequeath to one another.