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"
"God will add, God increases"
"greatest (superlative of great)"
"victory of the people"
"set apart, holy"
"my angel, my envoy"
"strong man"
"Held by the heel"
"divine gift"
"Cathay, the Middle Kingdom"
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.