And maybe he could even sell Fire Immunity potions due to the fact that, well, hes made of grass. even he needs a fire immunity potion.
I can see where you're coming from. Thank you for letting me know of some problems with the idea.I don't think Tree Man should only be able to spawn in/near just living trees. Not all worlds have these, and it'd limit what you can actually build to house Tree Man - and as someone who enjoys the freedom to build anything, I don't like this idea. IMO, his housing should be a bit limited, to keep him unique, but not too limited so what you can actually build is affected. What I think could be done is to make it so his house can only be built in the overworld and in a forest biome.
Maybe, instead of being a purity-only type of NPC, his wares, looks, dialogue etc. could depend on his environment. (Crimson, Corruption, Hallow...) He could be the only NPC able to spawn in a corrupted area. On the topic of his wares changing, let's say he sells a pet that's like the Moss Charger. The pet would be would be sold as a green bush when the house's surroundings are pure, but when the house's surroundings are corrupt, the pet would be a purple, thorny bush.
Of course, these ideas could complicate things, but it could work out and make the Tree Man one of the most unique NPC's.
Yeah, that's just my two-cents, but I love the concept of Tree Man.
Maybe if the world doesnt have a living tree, the world would need to be 70% pure maybe.I can see where you're coming from. Thank you for letting me know of some problems with the idea.