جَاءَنِي أَحْمَدُ
Translation: Aḥmad came to me.
جَاءَ: past-tense verb, built on fatḥ.
نِ: protective nūn.
ي: attached first-person pronoun, accusative object.
أَحْمَدُ: nominative subject with visible ḍamma, without tanwīn because it is a diptote.
Keep the two roles distinct: Aḥmad performs the action; the first-person pronoun is its object.