Arcadius sits next to 5 phonetic neighbors — Arcadia, Arkady, and Ignatius are the closest matches by sound. Most share Arcadius's Latin-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"of Arcadia, from the pastoral paradise"
"brave, valiant"
"gift of God"
"from Nazareth, consecrated to God"
"China, land of the Khitan"
"greatest (superlative of great)"
"victory of the people"
"may He add"
"my angel, my envoy"
"Held by the heel"
Similar sound: These names share phonetic patterns with Arcadius — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Greek/Latin origins, giving them the same cultural heritage as Arcadius.
Rhythm: Arcadius is a 4-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.