Were it not for his bizarre, upward-curving, rigid plumage (often making people misattribute him as part-Steel, though his actual types are Dark and Blood), Crinyx might pass for a natural depiction of a Utahraptor - his scales are a dark crimson, patterned with black stripes that are nearly invisible against his dark scales. Amber eyes further underline the reality of him.
Crinyx behaves very differently toward Legendaries, humans, and regular pokémon. As such, one can describe his personality as if he had three:
Around Legendaries, Crinyx is slightly socially awkward, quite eager for approval and praise, especially from the lady Legendaries that he wouldn't know how to approach if his life depended on it. Nonetheless, repeatedly treating him like a child will prompt him to harbour some resentment - so while he certainly respects Solalon's authority and ability to mediate, he occasionally has bouts of restrained anger toward the Light-type. The relationship he has toward the others can probably be best summarised as the best approximation of equality his inherent strictly hierarchic world view allows for.
Around humans, Crinyx is, in a word, a cruel monster who is glad to end lives, or, when in a particularly foul mood, torture the unfortunate victim for sheer entertainment. He can bring himself to tolerate most humans - the ones that don't presume themselves entitled to commanding pokémon around, at least - and can even harbour begrudging respect for individuals (something he feels for Jagdish Tsukinaka), but it takes an intense effort to get him to such a point.
Around regular pokémon, Crinyx is intensely protective, albeit stubbornly so and with little regard for whether they want his protection. He cannot fathom a human-pokémon relationship that is not inherently abusive, so he'll liberate all pokémon from their pokéballs that he can (usually after killing their trainer) and setting them free in an environment suited for their kind - the thought that the wild might be a scary place for some of them that have lived with humans for many years is foreign to him, and he will simply not understand it.
Ordered roughly from positive to negative, Crinyx…
With 'level' indicators for reference, in case someone wants to do a non-freeform run involving some levelling up on his part, since the species is unique:
All are inferred. Bold entries receive the same-type attack bonus.