Since the release of the trailer for Godzilla vs. Kong, fans have poured over practically every frame to glean what minor information they can, and wildly speculate what the tacit clues might represent. More overtly displayed, but equally worth mentioning, is the weaponry Kong is seen sporting at various points.
As well as being a formidable fighter, the great ape is also intelligent enough to use objects around him as weapons, as seen in Kong: Skull Island. In the decades since, his skill at utilizing such tools has evidently advanced to crafting them himself. One of his armaments is what looks to be the arm or leg bone of some huge beast (perhaps a vanquished skullcrawler) which has been broken and sharpened at one end to form a makeshift spear, which although undeniably primitive is also highly effective against a foe lacking tactical awareness.
However, far more notable is the ax Kong is seen to wield, which is demonstrated to be able to absorb Godzilla’s atomic breath and thus neutralize one of the lizard lord’s primary abilities that gives him an edge in battle. The shaft seems to be that same length of bone, and although obviously nothing official has been stated on the matter, it’s widely speculated that the blade is one of Godzilla’s own dorsal fins repurposed against him, presumably torn off by Kong in an encounter between the two earlier in the film, which would explain its resistance to weaponized radiation.
Since Godzilla: King of the Monsters saw the sometime Gojira being crowned as the titular monarch, it’s not too much to assume that in Godzilla vs. Kong we are to take him as possessing the more raw power of the two creatures, so the weaponry used by the last of the Titanus Kong will at least level the playing field.