The term 'remorseful one' can be described by three crossword solutions: RUER (4 letters), PENITENT (8 letters), and REPENTER (8 letters). RUER is a person who expresses regret or sorrow for a past action, PENITENT is someone who shows sincere remorse or regret for a wrong committed, and REPENTER is someone who has repented or expressed regret for a past action. All three words describe someone who is remorseful for something they have done in the past.