The phrase "a key character of" is correct and usable in written English.
It can be used to describe an important or significant aspect of a character in a story, film, or other narrative forms.
Example: "In the novel, the protagonist's resilience is a key character of her journey towards self-discovery."
Alternatives: "an essential trait of" or "a crucial aspect of".
Shorter anther of the m-type and O. meridionalis is a key character of annual species tended to self-pollinate.
A caged polecat appears as a key character of Saki's short story "Sredni Vashtar".
The evolution of the formation of the oral cone (a key character of siphonostomatoids) has led to controversial ideas.
This anterior-distal expression of Hoxd genes has been proposed to be a key character of the tetrapod limb that distinguishes limbs from fins [62].
A key character of Ephialtitidae, as well as of more primitive taxa (Symphyta, including Karatavitidae), is that the first abdominal segment (propodeum) is more or less convex (bent) transversally but even (little or not at all bent) longitudinally.
The Late Eocene to Early Oligocene genus Necromantis, often regarded as a megadermatid [ 31], differs from true megadermatids in several characters (including basisphenoidal pits, a key character of emballonurids, which is invariably absent in rhinolophoids) and most probably does not belong to that stock.
There's been uproar over the race change of a key character, rumours of costly reshoots and horrifically awkward promo interviews.
Who? Joey Essex is a key character in one of the UK's most popular reality TV shows, The Only Way Is Essex.
"The Walking Dead" has faced other challenges this year keeping a lid on crucial plot twists: the death of a key character was accidentally revealed ahead of schedule by a Web site selling a Season 2 Blu-ray boxed set (not to mention reports that the actor in question had been cast in another television pilot).
When "24" killed off a key character at the end of its first season, it was a huge deal, and rightly so.
In particular, we examine whether human-induced shifts in habitat structure have resulted in divergence in limb length, a key character in the diversification of Anolis lizards.
