This is a simple tip to make B Route Boss, Red Dragon, utterly easy on any difficulty, especially for Solo players, without leaving the initial room.
The video was done on Hard difficulty, with Lv63 Elf.
Once the fight is triggered, head to the bottom corner (whichever you prefer).
From then on, it's a simple case of dodging it's stomps, dodging the rocks that fall (screwed up a little in the beginning), and then just doing simple damage till it falls.
In this video's situation I mainly used Elemental Lore to deal the damage, but it can be done on any of the characters.
Sorry about the mistakes along the way. Wasn't able to perfect it as I had wanted to ^^;
