I dont need the Tarrasque to have regen for combat, per se.
I need it for the "Yay we won..../days later....Oh heck"! effect.
And since the 5e stat block doesnt have it (or beam weapon) boy will my players be surprised.
Typing this made me have an epiphany...what if the tarrasque arises to...
I dont find it important to have consistency.
My aaracokra probably have a totally different culture than the ones in your campaign. (and my elves etc.).
And thats a strength of the game. IMO.
Yeah, Sanderson (Mistborn, Warbreaker) was an example of good books and good details that I always reccomended.
I also bailed after Book 2 of Stormlight.
Much sadness.
All my dragonborn are either lizardfolk sports or divine emissaries. (the divine ones may have wings)
The lizardfok (lacerta in my world) as usual for sapient, either revere such mutations or cast them out.