No teammates, no helpers, no extra co-abilities, just Mym.
No game audio, sorry! The song is 'Overture' from the Resplendent Refrain event OST.
Thumbnail art is a wallpaper from reddit user u/Mackaged based off an ingame portrait of mym.

It's important to transform very early on, as Mym gains a 15% strength boost for the remainder of the quest, as well as a huge power boost on her second skill. One option is to save dragon and time the break to skip golems, and use dragon then, but my strat worked very well.

Equipment
Mym: 45 Mana Circles
MUB Agni
0UB Calamity Trigger
MUB Glorious Tempest
MUB Resounding Rendition