Complex sentence: Brawl appears in the live-action film who does not appear in any of the trailers (except for a very brief shot of his tank mode) and the most heavily armed Transformer seen in this continuity.
Split into simpler sentences: Brawl appears in the live-action film, though he does not appear in the trailers (except for a very brief shot of his tank mode). He is the most heavily armed Transformer seen in this continuity.