"For me, the first memory I have of what would eventually become Immortals Fenyx Rising was a bug on Assassin's Creed Odyssey where you'd be sailing on your ship, but instead of your human crew, you ended up having cyclopes as your crew". Ubisoft replied, pointing to the hundreds of live trademark examples that contain the word Monster, but Ubisoft essentially made a decision to rename the game instead of going through with a lengthy legal battle.
It looks like Monster Energy is the culprit behind the renaming of Gods and Monsters into Immortals Fenyx Rising. In an unlikely twist, it seems as though the beverage company Monster Energy might possibly be the reason for the Gods & Monsters name change. The company cited its gaming website and games industry sponsorships as evidence of its involvement in games and how it could lead to brand confusion.
Ubisoft denied all the allegations, of course.
One of Monster Energy's claims against Ubisoft's Gods & Monsters trademark
KitGuru says: What do you think of Monster Energy's claims? Yet ahead of September's Ubisoft Forward, the game's name was officially changed from Gods & Monsters to Immortals Fenyx Rising. What's interesting is that in Ubisoft's May 2020 answer to Monster Energy's notice of opposition, they deny nearly all of the claims. "So after that, the game changed a lot, to the point where we felt we needed a new name to be better aligned with that updated vision, so that's where we chose to change to Immortals Fenyx Rising, a name that combines the notion of the timeless aspect of the Greek mythology with the immortals".
Probably, the French publishing house decided not to waste time, effort, and money on disputes with Monster Energy: at that time the game was still waiting for a re-presentation and a partial change of concept.