No one in Sumatra had the gall to challenge the Boar King. Even pinnacle powerhouses like Raaha and Geugeu only intended to defend against the Boar King.
Brandal Brimgan wanted to fight the Boar King, but that was only to broaden his horizon, knowing full well that he wouldn't survive the fight. At least in Sumatra Chronicles, Yarsha Zahara schemed against the Boar King, but judging by the Mammoth Clan's annihilation, whatever she had planned hadn't taken effect yet.
Of course, how could anyone face an existence on Sumatra that was capable of killing literal Transcendents? It was a futile thought process.
In the present timeline, seven people dared challenge the thought. And they were the seven Mystic Paths, each carrying a certain objective towards their ultimate goal—to end the Boar King.