Theoden sits next to 3 phonetic neighbors — Theodore, Theron, and Aiden are the closest matches by sound. Most share Theoden's English-origin cluster, so the rhythm and vowel shape carry across the list.
You searched for names like
"king, lord of the people"
"cherished, beloved"
"of noble origin"
"peace of the father"
"champion, expert"
"court musician, entertainer"
"disciple of the dove"
"venerable, revered"
"invented blend of Bray and Lynn"
"peaceful ruler"
"consecrated, sacred"
"lion man"
"new house, bright place"
"new house (from Xavier root)"
"son of Dubhagan (little dark one)"
"mythic bird of rebirth and renewal"
"modern blend name, ray of light"
"boar-friend, warrior companion"
"kingly, of the king"
"saint of God, blessed by God"
"noble and ready"
Similar sound: These names share phonetic patterns with Theoden — similar vowel sounds, consonant clusters, or rhythm.
Shared roots: Several names on this list have Old English origins, giving them the same cultural heritage as Theoden.
Rhythm: Theoden is a 3-syllable name. Names with the same syllable count tend to feel interchangeable when you're narrowing your list.