During the Ashes and Dust event, the Glenden Wood Invaders quest line held a part where you could travel to different Meeting Halls, which were infested with Viamontion Invaders, and killing the boss there would give you a Helm and a title. This part was taken out in the Through Sacrifice, Strength event.
Travel to the following Meeting Halls (different level restrictions), talk to the NPC there, and kill the Strike Force Leader inside the Meeting Hall (see Table below)
Go back to Tomo Genza and receive level based xps, and a non-weildable Helm