When merrick tells the story of how he became zen-aku in the form of a narrated flashback in his story he removed his warrior helmet before he put on the wolf mask and in cole's flashback of merrick at the lake during the new moon the warrior helmet was nowhere to be seen but earlier in the episode when zen-aku becomes merrick because of the eclipse merrick removes his warrior helmet again.
In cole's flashback of merrick at the lake during the new moon merrick's boots, belt and gloves are nowhere to be seen.