From the Start, I Had a Run-Down Barracks, but My Fellow Countrymen Made Me a Great General

Growing Stronger by Devouring Metal or Anything Else Across the Myriad Worlds

The protagonist can devour tangible and intangible things, such as the Five Elements, and search for resources across the Myriad Worlds: the Marvel Universe, wuxia worlds, cultivation worlds, and so on. They don't learn lots of techniques, or maybe just one main technique, whose ability is to devour physical objects, mental energy, spirits, and so on.