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"
"son of Jack"
"slender"
"ruler of the people"
"my God is the Lord"
"shining, bright, luminous"
"uncertain; possibly Romani personal name with regional meaning"
"payment, brow, forehead"
"from Courtenay (place in France)"
"dweller in the forest"
"sacred name"
"creative modern invention"
"God is gracious"
"to heal"
"invented name with bold sound"
"strong fighter (from bar + hard)"
"modern American coinage"
"flowing river"
"wood, lumber, forest"
"made of earth, red earth"
"free man"
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.