walks alone upon the land to become lost in the wild.

他踽踽独行,背影渐渐消失在风中.

upon--在....上

upon the land--在大地上

become---系动词

Lost --adj.---消失

大地上孤独的游走，最终迷失在狂野之中。
upon = on
become lost中become作系动词用，后面直接加adj. 如：
become rich， become poor， become desperated