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