This orchestral and electronic arrangement of the Regi’s Battle Theme was made using MuseScore 4 / MuseScore Studio and MuseSounds, with the help of Fabio Moreno’s score from MuseScore.com. You can find the sheet music on my account at https://musescore.com/xauratronx.
Please do not use this arrangement without permission!
Let me know in the comments–what was your reaction to hearing this theme in game for the first time?
Copyright GAME FREAK and Jun’ichi Masuda.
Pictures found with Google Image.