Gigantamax Charizard .

If I modify this to be shiny, will it still be legal for online battles? (once trading to shy clean switch, and clean save naturally)? IM having a lot of troubles understanding the legalities of shiny Gigantamax Pokemon haha

If you don’t get the details using a Den Seed finder, it’ll appear legal on PKHeX but won’t be legal. Den RNG is pretty well understood at this point.

also note that modifying PID to use for battles online against unsuspecting opponents is against our rules.

Ahh thanks, that makes sense. I still only have a basic understanding of PKhEX.

And that's fair, makes sense.