Why do some trainers have black text boxes?

Question

i noticed that some trainers I find have black text boxes instead of a white text box. are they any different to those trainers?

Comments

Can you provide examples of which trainers have black text boxes?

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Good question, I never quite figured this out myself. I know that the yellow speech bubbles are for people who will give you items (like the man next to each PokeCenter).

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I think they might be trainers that are Champion level, like you (soon to be, before League) and Nemona.

Answer 1

The trainers with Black text boxes are "mighty trainers" , that are trainers stronger and sometimes with held items, like a leftovers. The First trainer with a special text box sai: " I am a mighty trainer and I put a leftovers in my Pokemon"