Paul Farquhar
Legend
Of course MToF has other trolls. Nobody says there is only one true troll. There is a world of monstrous possibilities out there for any GM in any game.
No idea why you thought that was ever a question?
That doesnt however require that one change how the "troll" as presented in the MM or the spell Chill Touch need to be changed to accommodate this.
As for your GM, I find it amazing that you seem to believe they got the regen from bits from 5e. Is it so outlandish to believe they might think it up on their own? Is it so unthinkable that they got an idea from any of the many books, movies, games with regenerating creatures where parts of the whole grew and thought "hey, this is cool and I can use it in DnD."
Are you so sure this is a DnD trope he got from 5e when I can recall Reptilicus in the way-before-and-dnd days where the key risk was blowing it up then pieces regen into hundreds - cue creepy claw regen scene at "The End?"
But hey, look, my bet is that if you just give your GM some credit now and again you will see it as not just repeating "tropes" and may be will actually surprise you - thinking up stuff all on their own.
Generally, if someone cites a source, it's a good idea to READ it before replying. It makes you look less foolish.
MToF p244 "A troll that is infused with waves of necrotic energy as it regenerates [can become a Rot Troll]". However, nowhere under troll in the Monster Manual is their a line that states "If the troll regenerates after taking x points of necrotic damage in the previous round there is a 5% chance that it will regenerate into a rot troll". Ergo, MToF directly contradicts the literal interpretation of game mechanics as spelled out in the Monster Manual.
Also, I never said my DM "got it from 5e". He "got it" because it is a very common D&D trope, irrespective of edition.