Ossan

おっさん

He is a veteran soldier in the Grania Republic with a high level of technical expertise. He initially lived with Mizuno but moved in with Souhei after Souhei rebuilt his house, which had previously been destroyed by the girls. Surprisingly, he is also an aspiring doujinshi creator.
His rank is unknown, but it is suggested that he holds the rank of either Master Sergeant or Sergeant Major.