mombot is to Chelsea, what GethN7 is to Brianna Wu. They are a fiercely anonymous twitter account that claims to be a random japanese housewife that is also really into video games and pop culture. It's clear they really are waist deep in japanese culture and probably not a weeaboo, but if they're really japanese then it's super-strange for them to be so closely involved in and able to comment on western internet drama like they are.
mombot is generally reactionary in posting and usually has a leg to stand on when poking SJW bears, which really pisses them off. They're most famous for fake-leaking details to a fake persona to several CON members, which baited them into doxing her, which they then revealed to be fake info and that they were doxing assholes despite their claims to the contrary. They also
identified the specific bathhouse/hot spring retreat Chelsea stayed at in fall 2018, which you'd have to be a resident or detective to do.
mombot is also a generally entertaining and informative twitter account that's worth following, highly recommend.