What happens if the Enlarge Person spell is cast on an already Large creature with reach?

Question

I have built my own race in one of my campaigns. I was wondering how the enlarge person spell would work on a Large creature who got the reach racial point giving him a reach of 10 feet.

I know that a Medium creature gets a 10-foot space and 10-foot reach with enlarge person, and the mythic enlarge person says a medium creature goes to 15ft space and a 10ft reach with mythic enlarge person.

Since my creature will be using enlarge person as a Large creature with the reach racial ability giving him a space of 10 feet and a reach of 10 feet, wouldn't enlarge person make him Huge, giving him a space of 15 feet and a reach of 15 feet?

Answer 1

The typical Large (tall) creature that becomes Huge (tall) sees its reach increase from 10 ft. to 15 ft.

While the spell mythic enlarge person would see a subject that's a Medium creature become a Huge (tall) creature with only 10 ft. of reach, if the creature is already a Large (tall) creature when it becomes the subject of the spell enlarge person, the creature should become Huge (tall) and its reach be 15 ft. according to the chart Creature Sizes on this page. The effects of the mythic enlarge person spell are only the effects of mythic enlarge person and shouldn't be generalized. (A Huge (tall) creature's space is nearly always 15 ft., by the way, so that's not really the issue here.)

Keep in mind that creatures that possess the type humanoid "are usually Small or Medium (with the exception of giants)." That is, if your homebrew Large (tall) race of humanoids also has the subtype giant, that's cool, but if it lacks that subtype, the game would also prefer it to have a type other than humanoid. And if the race does have a type other than humanoid, that race can't be the target of the spell enlarge person.