Demarco sits next to 4 phonetic neighbors — Marco, Demario, and Marcus are the closest matches by sound. Most share Demarco's Italian/Latin-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"of Mark, belonging to Mars"
"fort at Luguvalium"
"heroic, kingly"
"glowing coal, burning ember"
"smith, metalworker"
"of royal status"
"dark, coal-black"
"brave, courageous"
"of royal lineage, kingly"
"son of Hawkin, son of the little hawk"
"legendary warrior (fictional)"
"ruler of the people"
"heather hill, heath valley"
"truly brave, genuinely bold"
"man, mankind, mortal"
"son of the eternal king"
"army ruler, commander"
"one who bakes"
"strong, great warrior"
"noble, prince (from Arabic -mir)"
"just, righteous"
Similar sound: These names share phonetic patterns with Demarco — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Italian/Latin origins, giving them the same cultural heritage as Demarco.
Rhythm: Demarco is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.