 Nyorai mberi kweiyi ndima - Dewar akanyoresa kare, achibatanidzwa neNew Zealand Expeditionary Force achibva musi wa15August 1914 achienda kuGerman Samoa. Pakudzoka kwake akazvipira zvakare, akabatana ne9th Wellington Mounted Rifles semuchina wemapurisa uye aive akavakirwa paAwapuni Racecourse, Palmerston North; akakurumidza kukwidziridzwa kuva sarjento. Musi wa 16 Gumiguru 1914, mushure mekudzidziswa, Dewar akakwira Orari kuWellington achienda kuEgypt. Ikoko, Dewar akatungamira chikwata che rugby cheWellington Mounted Rifles mumitambo yakati wandei vachipesana nemamwe ma regiments vachikunda First Australian Light Horse, Canterbury Mounted Rifles, neAuckland Mounted Rifles regiment yake isati yasvika musi wa 8 Nyamavhuvhu 1915 kuAnzac Cove, Gallipoli. Maawa makumi maviri nemana gare gare, musi wa 9 Nyamavhuvhu 1915, Dewar akarasikirwa nehupenyu hwake pakurwiswa kweChunuk BairAlbert Downing akaurawa muchiito chimwe chetecho, Wevatema Vose wokutanga kuurawa muhondo. Sergeant Henry Dewar anoyeukwa paChunuk Bair NZ Memorial Turkey Panel 4. 