Sorry for the vague title, but the situation is too complicated to sum up into a short blurb.
Among my hobbies, I play the card game Magic: The Gathering, and recently there was a high profile story about a professional Magic player (in that his day job is literally just playing Magic, mostly streaming) who got into some legal trouble with the company. If you would like additional context on what I'm about to present, Google the name "Owen Turtenwald". I'm a bit curious about how his situation would play out; I've read various Reddit posts and so on on the topic, but I'm interested in thoughts of people who actually know what they're talking about rather than Reddit randoms.
My understanding of the facts of the case are as follows:
There is a girl named Mary Rourke who seems to (best I can tell from reading Reddit/Twitter/etc) have had some sort of sexual relationship with Owen.
Mary accused Owen of sexual assault (or harassment, or something of that nature), without proof (or at least without proof in public; perhaps she has proof and has shown it to people on a need-to-know basis, but at least in the public realm there is no proof)
Owen was licensed by Wizards of the Coast LLC (WotC), a subsidiary of Hasbro Inc, as a member of the "Magic Pro League" (MPL), which in addition to the prestige of that association also has a very sizable monetary value (and additional real monetary value providing Owen does some other things which he can opt into if he wants). You can Google for the details of precisely what the deal is, but the bare minimum is a $75,000 USD/year contract for playing Magic in its various digital forms on stream regularly, plus additional perks.
Due to the accusations by Mary, WotC terminated Owen's contract as a member of the MPL, and furthermore I believe Owen has been banned from playing Magic at most high-profile events (I am not sure of that last part). Keep in mind this is Owen's full-time job, he's not by any means a "casual" player.
As of the moment, Mary hasn't presented any evidence to back up her claims against Owen (as far as I know), it's simply a he-said-she-said situation.
Nobody except Mary in this situation has formally accused Owen of any misconduct. Neither Hasbro nor WotC has made an official public statement on the matter whatsoever except to state the consequences for Owen (e.g. expulsion from the MPL)
Apparently (I read on Reddit), WotC presented Owen with a settlement agreement including damages for defamation. None of the negative consequences of the ordeal (e.g. expulsion from the MPL) were reversed.
Question: Given the above situation (and whatever additional information you can find on Google which I may have missed in my assessment), if Owen were to tell WotC to take their settlement offer and shove it, what might be the legal consequences for WotC/Hasbro? Would Owen be able to sue them, and on what grounds? What would be required of WotC/Hasbro to defend themselves from such a lawsuit? What might be Mary's responsibility in all of this?